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SHB-900 - Rockwell Automation

1. 9 2 5 8 Enabling device continuously actuated start control see standard 9 2 6 Combined start and stop controls C O E 9 2 7 1 Cableless control remote radio infrared etc Power disconnection required at the operator Prevent unauthorized use the control station O Mark on the operator the operated machine 9 2 7 2 Control limitation only the intended function on the proper machine shall react L L L to remote control 9 2 7 3 In hazardous condition the remote control require an emergency stop device 9 2 7 5 Use of more than one remote operator control station only one control station is operable at the same time 9 2 7 6 Battery powered remote operator control station variation in battery voltage shall not create hazard Low battery warning required 9 3 1 Restoration of interlocked safeguards shall not initiate machine motion 9 3 2 Overtravel limits required when hazardous condition can occur 9 3 3 Operation of auxiliary functions Functions causing hazard shall have interlocks LJ pressure etc 118 9 3 4 Interlocks required between control elements which can cause hazardous condition O s
2. All live parts are disconnected before the door can be opened defeater allowed Live parts are protected to IP2X or IPXXB or All live parts are protected to IP2X or IPXXB 6 2 3 All live parts are completely covered by insulation 6 2 4 Residual voltage discharged to 60 V in 5 seconds 6 3 Protection against indirect contact insulation failure 6 3 2 or 6 3 3 6 3 2 2 Use of Class II equipment or 6 3 2 3 Electrical separation see 413 5 of I EC 364 4 41 or 6 3 2 4 Isolated supply one insulation failure not create danger 6 3 3 Automatic disconnection in case of insulation failure g g 204 1 Ref 6 4 Description of Standards Protection by PELV Applicable Applicable Approved Nominal voltage 25 V a c or 60 V d c dry location or 6 V a c or 15 V d c and One side of the circuit is earthed and Electrically not connected to other circuits and Conductors physically separated from other conductors and Plugs and sockets are not interchangeable with other voltages 6 4 2 Source of PELV isolating transformer or battery or other equivalent means
3. SU Starting GUtte se he eee een Ce ee ENY 19 3 1 EN 292 Basic concepts of machine safety 19 STEN CMDR CIV CS ee tee EEE A E E S E EE A eee 23 53 REMC Directive re rr te re E Ce ee 25 OA he EON Voltar e Ditective 2 E E 25 3 5 The Product Liability Directive ee 26 3 6 Examining Type A B and C Standards 27 Chapter 3 The Road Map continued 3 7 Annex I Essential Health and Safety Requirements 29 3 8 Risk assessment EN 1050 005 30 3 9 Risk estimation EN 1050 and EN 954 31 3 10 Performance categories EN 954 33 3 11 Risk performance and selection 39 Be lb2 eS UINETVANY e Ge gettane a aaa ea cok a antl ae hk ae 40 Chapter 4 Post Design and Construction Requirements 4 0 So you ve complied with requirements now what 1 24225 2452 2 440 46 AMD WVfOrmnanOm TOE Se 4 6 6 i e E 46 4 2 Advice for drafting information for use 47 1o othe tecnmcalbilen eee E eee 49 44 Declaration of Conformity 4 4 51 4 50 CNVOS CETE e ee ee 53 AO PCEM A ee ret E 55 Chapter 5 Safety Category Requirements 5 0 Why include safety and safety related components 58 5 1 Well tried components and design principles 59 5 2 Direct opening action contacts n seasea 59 Do Positively driven contacts 4 2 ss ee eee 62 Ob PNIMEEBINS edine S 4 yo Goad o a boos au nnoaauaaae 63
4. A global road map The purpose of this book is to provide designers quality assurance managers sales directors and others with a road map for understanding the key elements of the CE marking process It introduces the reader to key European requirements in an easy to understand format it walks OEMs through the basic CE marking steps it helps establish realistic expectations and it directs readers to further resources Where appropriate much of the language used stays close to the original wording of the directives and standards The second portion of this book provides safety component application examples The authors reiterate that this book serves as a road map for making a comprehensive process more manageable It is not intended to be a substitute for thoroughly reading all appropriate directives and standards 1 2 Does the Machinery Directive apply to me The definition of machinery is 4n assembly of linked parts or components at least one of which moves with the appropriate actuators control and power circuits etc joined together for a specific application in particular for the processing treatment moving or packaging of a material See Figure 1 0 This definition also covers an assembly of machines functioning as a whole as well as interchangeable equipment modifying the function of a machine Any manufacturer whose machine fits the above description would be well advised to continue reading OPERATO
5. Chapter 5 Safety Category Requirements continue SS VRECUNUANCY iG out ee Sa eae cena Oe Mie ae 63 5 6 Normally energized circuits 3 4 cc oy ce ae 64 5 7 Control circuits and performance categories 66 5 8 Category B and Catesoryol cree eee ae ees 66 Se EAL ORV ee wraps cea ens haat gene Roem a ee aA ee MENT 69 5 10 Category 3 and category 47 25 2 cee es 70 Chapter 6 Safety Concerns for Power Related Products 6 0 Operational functions ee 76 Gra Contactreiability er ee a eh cen a ete nee 76 GO eiMultipic taultdctection e E 71 Gide E MOtOn Protect OnE a ae ieee ee ee 77 6 4 Safe separation of circuits to avoid electric shock 79 6 5 Protection against electric shock 7 24 2 7 25 81 6 6 Protection against indirect contact 81 Chapter 7 Frequently Asked Questions FAQs a Be Picture AOS vere ae ee era E aes trees eect 86 Component FAOST iets eee core see ee cea ee 91 Rockwell Automation Allen Bradley FAQs 93 Glossary of Terms Appendices Appendix A Select Type B standards 104 Appendix B Electrical equipment of machines 107 Appendix C EHSR Annex I of the Machinery Directive 7425 128 Appendix D Some significant faults and failures 135 Appendix E Standards and characteristics OF Sabety TUNCHIONS 42 0 5a 5 ene ees 137 Appendix F Sample DOCs 72s ee 139 Appendix G Annex IV equipm
6. 3 2 9 7 2 6 of EN 775 3 7 10 3 13 4 5 5 9 6 2 of prEN 1921 Muting 5 9 Manual suspension of 5 10 3 7 10 1 2 5 9 2 4 of EN 60204 1 6 10 of EN 775 5 8 of 137 safety functions 4 1 4 prEN 1921 138 Safety Function Additional Information Characteristic Further Not Requirements Standards Annex A Part 1 Part 2 Part 2 Fluctuations loss and 5 11 3 7 8e 1 2 6 4 3 7 1 7 5 of restoration of 1 5 3 EN 60204 1 power sources Unexpected start up 3 7 2 1 2 3 1 2 6 EN 1037 5 4 of 1 2 7 EN 60204 1 Indications and alarms 3 6 7 1 2 2 14 6 EN 457 prEN 842 5 6 of prEN 1921 5 3 1 7 0 1 7 1 prEN 981 10 4 11 3 of EN 60204 1 EN 60447 Escape and rescue 6 1 2 1 2 2 4 5 6 of trapped persons Electrical equipment 3 9 1 5 1 1 5 7 EN 60204 1 Electrical supply 1 5 1 4 3 of EN 60204 1 Other supply 1 5 3 5 1 4 of EN 982 5 1 4 of EN 983 Covers and enclosures 13 4 of EN 60204 1 EN 60529 Pneumatic and hydraulic 3 8 1 5 3 EN 982 EN 983 equipment Isolation and 6 2 2 1 6 3 EN 1037 5 3 6 3 1 energy dissipation of EN 60204 1 Physical environment 3 7 11 4 4 of EN 60204 1 6 9 of EN 775 4 3 4 5 of and operating conditions prEN 1921 Control modes and 3 7 9 1 2 5 9 2 3 of EN 60204 1 6 10 of EN 775 mode selection 3 7 10 Interfaces connections 1 5 4 9 1 4 11 15 4 of 1 6 1 93 EN 60204 1 Interaction between 3 7 8e 9 3 4 of EN 60204 1 different safety related parts o
7. ISO 1 rue de Varembe CH 1211 Geneva 20 SWITZERLAND Phone 011 41 22 749 0111 Fax 011 41 22 733 3430 Internet www iso ch Comments Direct source of ISO standards Will accept credit cards as part of phone order I 4 British Standards Institution 389 Chiswick High Road London W4 Notified Bodies 4AL UNITED KINGDOM A Notified Body is a type of Phone 011 44 181 996 9000 independent testing laboratory that Fax 011 44 181 996 7400 an EU member state has determined Internet www bsi org uk to be qualified to perform testing and certification functions relating Comments Source of CEN and RA to specified directives The member CENELEC standards once they are state notifies the Council of the published English language version European Community EC and the laboratory of its qualified status 5 Global Engineering Documents ne ine AAA S E 7730 Carondelet Ave Suite 407 procedure by which a Notified Body St Louis MO 63105 ascertains and certifies that an Phone 1 800 854 7179 apparatus satisfies the provisions Fax 1 314 726 6418 Comments Source for a variety of the applicable directive s of standards 6 CEN European Committee for Standardization Central Secretariat rue de Stassart 36 B 1050 Brussels Belgium Phone 011 32 2 550 0819 Fax 011 32 2 550 0811 Internet http tobbi iti is cen welcome html 7 CENELEC European Committee for Electrotechnical Standardizati
8. in Rated Voltage Phase Hz DC 204 1 Ref Description of Standards Applicable Applicable Approved 4 1 0 0 0 Annex B has been completed 4 1 Risk assessment has been performed by the customer 4 2 2 3 4 Selection of equipment List of equipment CE marked add DOC not CE marked TCF number 4 3 Electrical supply Standard or Annex B stated in the instruction manual 4 4 Physical environment and operating conditions 4 4 2 Electromagnetic compatibility EMC devices not marked with CE see standard 204 1 Ref Description of Standards Applicable Applicable Approved 4 4 3 Ambient air temperature 5 to 40 C or Annex B stated in the instruction manual 4 4 4 Humidity 50 at 40 C or equivalent stated in the instruction manual 4 4 5 Altitude up to 1000 m or Annex B stated in the instruction manual 4 4 6 Contaminants enclosure type IP rating 4 4 7 Ionizing and non ionizing radiation microwave ultraviolet lasers X rays etc see Annex B stated in the instruction manual 4 4 8 Vibration shock and bump including
9. 1 2 3 Category selection B 1 to 4 Categories for safety related parts of control systems Preferred categories for reference points e Possible categories which can require additional measures O Measures which may be overdimensioned for the relevant risk Fig 3 5 Guidelines for risk estimation from EN 954 1 Annex B NOTES 1 Annex B is informative not normative The correct use of EN 954 1 requires attention to ALL of its clauses not just the requirements for its categories 2 Two common misconceptions occur with the categories noted in EN 954 1 that they represent levels of risk and that they are hierarchical THIS IS NOT TRUE The categories should be considered as reference points for the performance of a safety related part of a control system with respect to the occurrence of faults 3 A weakness of EN 954 1 is that the categories are basically defined in terms of performance under fault conditions As such there is no mechanism for culturing the choice of a given performance category by the comparative reliability of differing risk abatement options or technologies The 1996 version of EN 954 1 is currently being reviewed to address this situation Once a hazard is identified it is important to know if it can be identified by physical means i e watching the machine move or only by technical means i e indicators Other important aspects which influence the selection of parameter P Possibility include e Operatio
10. 18 5 Installation diagram preliminary work supply cables overcurrent protective devices foundation space for removal and servicing interconnection diagram 18 6 Block system diagrams and function diagrams see IEC 1082 1 Section 2 and IEC 1082 2 Section 3 18 7 Circuit diagrams required 18 8 Operating manual for set up and use of the equipment required 18 9 Maintenance manual required 204 1 Ref 18 10 Description of Standards Part list for spare and replacement parts required Applicable Applicable Approved 19 Testing and verification 19 1 Product standards apply if product standard is not available the following tests apply Equipment and technical documentation is in agreement Continuity of the PE circuit Insulation resistance see 19 3 Dielectric voltage test see 19 4 Protection against residual voltages see 19 5 Functional test see 19 6 19 2 Continuity of the protective bonding circuit After installation loop impedance test per 6 1 2 of IEC 364 6 61 For small machines less than 30 m bonding
11. 1997 Allen Bradley Company Inc Printed in USA
12. 392 EEC with amendments and interpretations Scope of the directive Primary obligation of the member states Obligation of the manufacturer Free movement of machinery Use of standards as a means of assuring conformity Establishment of committees to deal with matters related to the directive Establishment of the authority of member states to review conformance of machinery Requirements of the manufacturer to demonstrate conformity Establishment of the authority of member states to designate Notified Bodies CE marking Notification and rights of manufacturer in case of claim of non conformity by member states Availability of information on all relevant decisions Effective date and transition periods Repeal of conflicting directives Fig 3 3 3 3 EMC Directive Apparatus must comply with the EMC Directive when it is liable to cause electromagnetic disturbances or its performance is liable to be affected by such disturbances This is particularly true if the disturbance results in a sudden risk increase which then becomes a safety issue e g initiation of an unexpected motion as the result of an inductive proximity sensor triggering On accidentally The EMC Directive states that all apparatus placed in the EU EEA market shall be constructed so that The electromagnetic disturbance it generates must not exceed a level allowing radio and telecommunications equipment and other apparatus
13. Annex I Essential Health and Safety Requirements 3 7 Riskeassessment BN 1030 o255 3 eee ees 3 8 Risk estimation EN 1050 EN 954 oe Performance categories EN 954 3 10 Risk performance and selection 5 3l il The Road Map Familiarization with the basic concepts of machine safety Read and understand the Machinery Directive Review other Directives for applicability Examining Type A B and C standards Is there a C Type standard available Yes but cannot fully comply Design and construct in accordance Conduct Risk Assessment with as many as possible of PE C standard requirements and other A s eee amp B appropriate measures from Dee ee as needed A amp B standards i Design and construct in accordance with all requirements of C Type standard Verify test or inspect that machinery meets requirements of applicable sections of Annex Create Information for use Vv Generate Technical File Can you self certify No y Submit for EC Type Examination Yes Sign Declaration of Conformity 4 Affix CE marking Fig 3 0 Basic approach to obtaining CE marking Note A B and C standards are explained in section 3 6 of this book Starting out Viewed graphically see Figure 3 0 the process of obtaining CE marking looks quite manageable The authors suggest that manufacturers approach the task as a series of steps
14. L pushbutton Fig 5 6 Potential category B control circuit 145 Gate Interlock Pusher Controls Overload Fig 5 7 Potential category I control circuit 146 Safety Interlock Robot Controller Overload 147 Fig 5 8 Potential category 2 control circuit Overload Fig 5 8 Potential category 4 control circuit 148 The Road Map This handbook provides machine designers quality assurance managers sales directors and others with a road map for understanding the Machinery Directive and CE marking process Its contents include e An easy to follow introduction to the Machinery Directive and key European Norms standards The basic CE marking steps Direction to further resources e Important guidance on risk estimation and assessment e A review of safety and safety related components for control systems e Answers to frequently asked questions e Excerpts from selected directives and standards Most importantly Understanding the Machinery Directive provides some straight talk about what the language of the directives and standards really requires N Rockwell Automation Rockwell Automation helps its customers receive a superior return on their investment by bringing together leading brands in industrial automation creating a broad spectrum of easy to integrate products These are supported by local technical resources available worldwide a global network of system solutions providers an
15. a complete listing Manufacturers of machinery and or devices listed in Annex IV have two paths to choose from to obtain CE marking 1 If the manufacturer has fully complied with EHSRs and all relevant standards and is confident of compliance the manufacturer must either e Send a TF to a Notified Body who will A acknowledge receipt of the file and keep it or B verify that the standards are correctly applied and issue a certificate of adequacy to that effect Note that in the case of the former the Notified Body does not assess the file it merely keeps it as reference e Or submit an example of the equipment to a Notified Body for an EC type examination If the manufacturer has correctly applied the applicable standards the Notified Body will issue a EC type examination certificate 2 If the manufacturer has not fully complied with the EHSRs and relevant standards or if no relevant standards exist for this type of machinery the manufacturer must submit an example of the equipment to a Notified Body for an EC type examination see Appendix E for a list of information OEMs need to submit for an examination If the manufacturer has correctly applied the applicable standards the Notified Body will issue an EC type examination certificate ANNEX IV MACHINERY SAFETY COMPONENTS TO NOTIFIED BODY ALL OTHERS Most manufactures can self certify conformity with the Machinery Directive Verify test or inspect t
16. and think of it as a process for incorporating safety into machinery This section cites specific standards and directives and quotes sections of them The intent is to expose readers to the standards in a controlled manner and to direct readers to the sections that will be most helpful to them Familiarization with the basic concepts of machine safety Read and understand the Machinery Directive Review other Directives for applicability 3 1 EN 292 Basic concepts of machine safety European Norms ENs commonly referred to as standards state specific requirements of the directives The key standards for clarifying the Machinery Directive are EN 292 1 and EN 292 2 Safety of machinery EN 292 1 serves as a good introduction because it provides machine designers with basic concepts and terminology of machine safety e g safety critical functions moveable guard two hand control devices trip device descriptions of hazards e g mechanical electrical thermal and strategies for risk assessment and reduction see Figures 3 1A and 3 1B For more information on the terminology used in the standards obtain a copy of ENV 1070 a provisional standard now being developed on terminology Supplier Information provided by the user or user community pp as to intended use tasks accident history possible misuse Determine the limits of the machinery or system Task and hazard identification Risk estimation Risk eva
17. and using any other design provided that resulting performance meets the performance required by the applicable directives It will be approved if they can prove compliance with the directives Can obtain a list from Rockwell Automation of all its CE marked control components What other CE information does Rockwell Automation have Yes Please ask your local Rockwell Automation representative for a list Information about our products and the CE mark in general is available on Rockwell Automation s Internet site at www ab com Click on the Allen Bradley and the CE mark button What type of approval does A B have Most Rockwell Automation products of the type discussed in this handbook are covered by the Low Voltage and EMC Directives Products meeting these directives bear the CE mark 93 A Declaration of Conformity statement is available for these products 46 47 How can obtain the Declaration of Conformity DOC for a Rockwell Automation product If you would like a DOC ask your local Rockwell Automation representative The information is also available on Rockwell Automation s Internet site at www ab com Click on the Allen Bradley and the CE mark button What NEMA designed products will A B have CE marked Various products from each major business group carry CE marking Please ask your local Rockwell Automation representative for a list The information is also available on Rockwell Automation s Int
18. as gate interlock switches and emergency stop pushbuttons do not need third party certification under the Machinery Directive and they are not Annex IV listed To minimize risk in case of failure or put another way to help ensure the availability of the safety function the EU standards provide guidance for the design and use of safety components 5 1 Well tried components and design principles Categories 1 through 4 for the safety of control systems require the use of well tried components and principles Some of these are e Direct opening action contacts positive opening operation this applies to break contacts normally closed contacts e Positively driven contacts this applies to devices with make and break contacts normally open and normally closed contacts e Anti tease features for emergency stop buttons e Redundancy diversity and combination of positive and negative modes e Normally energized circuits for safety functions 5 2 Direct opening action contacts EN 60947 5 1 which covers electromechanical control circuit devices and switching elements defines direct opening action as the achievement of contact separation as the direct result of a specified movement of the switch actuator through non resilient members e g not dependent upon springs Direct opening action devices couple operating force to the contacts so that the force breaks open contacts that may have welded together see Figure 5 0 They
19. button must be pushed to restart the system This protects the operator from accidental or unexpected motion if the power were to come back on while the operator was in the hazard zone Designer s Discretion Machine designers must use their own discretion after making a risk assessment when identifying categories and specifying safety functions and components Remember the directives and standards do not specify which safety aspects designers shall use they just provide guidance 5 9 Category 2 From category 2 upward the higher degree of safety results from the structure of the safety circuits and the prevention and detection of faults i e not only the choice of components This category requires a check of the safety function at suitable intervals e g at the beginning of each operation cycle upon start up or at established times during the cycle it is the manufacturer s responsibility to specify an appropriate interval If a fault is detected during start up the machine must be prevented from starting If the safety function is lost during a cycle the loss must be detected at the next start attempt Circuits for category 2 machinery perhaps a pick and place robot has been added to a fast moving conveyor must focus on fault prevention Two fault prevention techniques include adding redundancy and using contactors with normally energized output circuits Figure 5 8 shows the circuit d
20. do not use a spring interface 59 because a spring may have insufficient strength to break a weld or it could fail see Figure 5 1 Direct opening action designs are required for disconnect switches emergency stop switches safety limit switches cable pull safety switches and safety gate interlock switches see Figure 5 2 for some examples These products will have the symbol for direct opening action on them shown like this wile zl Direct opening action or positive opening Welded contact forced open Fig 5 0 Direct opening action assures safe E Stop functions a ay Contacts welded e _ Spring force insufficient Broken spring contacts to break weld fail to open Fig 5 1 Potential failure modes of negative opening contacts 61 Machine stopped Machine operating LSD IN W rN A my ES f 2 A lity Ni oe Fig 5 2 Direct opening action helps assure separation of contacts 5 3 Positively driven contacts EN 60947 5 1 defines positively driven operation as an operation which is designed to ensure that contacts of a mechanical switching device are in the respective positions corresponding to the open or closed position of the main contacts A draft document of prEN 50205 Relays with p
21. early restricting the consequences of a fault e g grounding of equipment Newly developed components and safety principles may be considered equivalent to well tried if they fulfill the above mentioned conditions Note On the level of single electronic components alone it is not normally possible to meet category requirements See Appendix D for a list of some significant faults and failures for various technologies Safety categories Safety hierarchy Designers should note that performance categories do not indicate a safety hierarchy i e category 4 is not necessarily safer than category 1 Rather these categories state the required behavior for a safety system in relation to its resistance to faults Thus according to the performance category required machine designers must select safety related parts on their ability to resist faults i e both reliability and availability of the safety function must be considered Safety reliability However designers must not confuse reliability and safety For example a system with unreliable components in a redundant structure can provide more safety than a non redundant system with better components This concept is important because in applications where the consequences of failure are serious safety requires the higher priority regardless of the reliability achieved Designers may want to refer to Annex D of EN 954 for more details C
22. facilitates an agreement between the user and supplier on basic conditions and additional user requirements to ensure proper design application and utilization of the electrical equipment of the machine see 4 1 of EN 60204 1 Name of manufacturer supplier Name of end user Tender Order no Date Type of machine serial number 1 Are there to be modifications as allowed for within this standard YES __ NO__ Operating Conditions Special requirements 4 4 Ambient temperature range Humidity range Altitude An A UQ N Environmental e g corrosive atmospheres particulate matter EMC 6 Radiation 7 Vibration shock 107 f 8 Special installation and operation requirements e g flame retardant requirements for cables and conductors 11 12 13 14 15 16 108 Power supply ies and related conditions 4 3 Anticipated voltage fluctuations if more than 10 10 Anticipated frequency fluctuations if more than in 4 3 2 Specification of short term value Indicate possible future changes in electrical equipment that will require an increase in the electrical supply requirements Indicate for each source of electrical supply required Nominal Voltage V AC DC If AC number of phases frequency Hz Prospective short circuit current at the point of supply to the machine kA rms see also question 15 Fluctuations outside values given in 4 3 2 Type of power supply earthing TN Sy
23. fitted with one or more emergency stop devices to enable actual or impending danger to be averted Also helpful are the standards supporting the directive which provide a process for identifying hazards assessing risk and implementing measures to improve reliability reduce the possibility of failure or increase the probability of detecting a failure Ultimately the directives reduce bureaucracy and help OEMs make their products as safe as possible while being realistic about design and usage demands In the event of an accident the directives also may offer proof of due diligence S ell The designer encountering European safety laws for the first time may feel overwhelmed by all the new safety related numbers and acronyms Acronyms Numbers Help CHE Ue peat amManke lessee tute renner ere E 2 0 So what directives should I examine P Standards to clarify directives 74 02 2 522 ae a Sources tor standards 2 24 un0ce nee oe nee eee 23 CE Markin 2E A N E E ar aan O rae mere aero 2 4 Intenpretationsimay vary 1 ee 6 ee ee ee 23 Applying components properly 2 6 2 0 The European market The countries of the European Union are as of January 1 1997 Austria Germany Netherlands Belgium Greece Portugal Denmark Ireland Spain Finland Italy Sweden France Luxembourg United Kingdom The EU countries plus Iceland Liechtenstein and Norway form the European Economic A
24. guards see 3 22 3 in EN 292 1 restricting access to the moving parts in those zones where it is necessary for the process Fig 3 2 EN 292 2 provides information on how to incorporate safety into a machine such as this diagram for choosing safeguards Familiarization with the basic concepts of machine safety Read and understand the Machinery Directive Review other Directives for applicability 32 The Directives From the definition of machinery to a machinery manufacturer s ability to demonstrate conformity to applying the CE marking the Machinery Directive sets forth the laws with which all manufacturers must comply Although moderately long see Figure 3 3 and written like a legal document all manufacturers must read the Machinery Directive It is the law and ignorance of the law is no excuse for failing to comply Articles 1 14 of the Machinery Directive are written in legal jargon Conversely Annexes I VII of the Machinery Directive are relatively easy to follow The Annexes are very important and particularly Annex I which covers Essential Health and Safety Requirements EHSRs After the Machinery Directive manufacturers must review other directives for applicability note multiple directives often apply The three directives most likely to apply to machinery using control products are the Electromagnetic Compatibility EMC Directive 89 336 EEC 23 the Low Voltage LV Directive 7
25. guide moving components loosening of fixtures e g by vibration wear e g runners latches rollers misalignment of parts environmental influences e g corrosion temperature 136 Appendix E Standards and characteristics of safety functions Reference list of some standards giving requirements for characteristics of safety functions as of March 1 1997 Safety Function Additional Information Characteristic EJ EN 292 aie Not Requirements a Annex A Part1 Part2 Part 2 Definitions 3 3 clause 3 of clause 2 of EN 60335 1 EN 60204 1 Design principles 4 2 3 1 2 1 1 2 2 9 4 of EN 60204 1 clause 22 of EN 60335 1 1 2 7 1 54 cl 5 6 of EN 775 cl 5 of prEN 1921 Ergonomic principles 44 4 9 3 6 1 2 29 1 clause 10 of 6 2 of EN 775 3 7 8a EN 60204 1 4 6 of prEN 1921 Stop function 5 2 3 7 1 1 2 4 9 2 2 9 2 5 3 7 12 of EN 60335 1 5 11 3 7 8b 1 3 5 of EN 60204 1 of prEN 1921 Emergency stop 5 3 6 1 1 1 2 4 EN 418 9 2 5 4 6 4 2 7 2 5 of EN 775 function of EN 60204 1 5 11 2 of prEN 1921 Manual reset 5 4 6 1 1 1 2 4 EN 418 9 2 5 4 6 4 2 6 4 3 7 6 of EN of EN 60204 1 775 6 4 3 of prEN 1921 Start and restart 5 5 3 7 1 1 2 3 9 2 1 9 2 5 1 9 2 5 2 6 10 7 2 5 7 3 1 9 3 4 3 7 2 1 3 5 9 2 6 of EN 60204 1 of EN 775 Response time 5 6 3 2 A 3 A 4 of prEN 999 Safety related af 3 7 9e 7 1 9 3 2 9 3 4 4 2 of EN 775 11 8 of parameters of EN 60204 1 EN 60335 1 Local control function 5 8 3 7 9
26. in the EU can themselves certify conformity of the product to the essential health and safety of the applicable Directive s and to other relevant requirements STANDARDS See EUROPEAN NORM TECHNICAL FILE Documentation required by directives File compiled by the manufacturer and placed at the disposal of the national authorities should they so request Note the term Technical Construction File TCF is referred to in the EMC directive TYPE A STANDARDS Fundamental safety standards that cover the basic concepts principles and general aspects of all machinery TYPE B STANDARDS Group safety standards They cover one safety aspect one type of safety related device and a wide range of machinery TYPE C STANDARDS Detailed safety requirements for a particular machine or class of machines WELL TRIED A well tried component for a safety related application is a component which has been widely used in the past with successful results or made and verified using principles which demonstrate its suitability and reliability for safety related applications 101 Appendices Appendix A Select Type B standards Type B1 and B2 standards basic safety standards deal with one safety aspect or one type of safety related device for a range of machinery The following is a brief list as of March 1 1997 General EN 954 1 Safety related parts of control systems EN 953 Design and construction of guards EN
27. loop not connected to the power source inject 10 A from a PELV source and the measured voltage drop shall not exceed Table 9 values 19 3 Insulation resistance tests Measured with 500 V d c not less than IMQ For exception see standard 19 4 Dielectric voltage tests between circuits and bonding Twice the rated voltage or 1000 V for 1s for details see standard 19 5 Protection against residual voltages see 6 2 4 19 6 Functional tests related to safety 19 7 Retesting after changes or modifications 127 128 Appendix C EHSR Annex of the Machinery Directive From a control systems perspective Section 1 of Annex I is probably the most important part of the EHSR To give readers an idea of what to expect when reading the EHSRs this Appendix notes some of the topics in Section 1 OBTAINING AND UNDERSTANDING THE COMPLETE EHSRs IS AN ABSOLUTE REQUIREMENT OF THE LAW THE FOLLOWING LIST SHOULD NOT BE CONSTRUED AS COMPLETE OR A SUBSTITUTE FOR THE EHSRs ESSENTIAL HEALTH AND SAFETY REQUIREMENTS From 89 392 EEC Annex I as of September 1997 1 1 General remarks 1 1 2 a b Definitions Principles of safety integration Machinery must be so constructed that it is fitted f
28. machine generated see Annex B stated in the instruction manual 4 5 Transportation and storage 25 C to 55 C 4 6 Provisions for handling see also 14 4 6 4 7 Installation and operation installation drawing required 5 1 Incoming supply conductor termination marking single power source Multiple power source see 5 3 1 Neutral conductor color marking terminal marking N see Annex B No connection between N and PE 5 2 Terminal for connection to the external protective earthing system terminal marked with PE Terminal size Conductor size material copper insulation green and yellow Load PE connectors marking 417 IEC 5019 111 i 204 1 Ref 5 3 Description of Standards Supply disconnecting isolating device Applicable Applicable Approved 5 3 1 Disconnect for each incoming source 5 3 4 Exceptions lighting circuits for maintenance plug and sockets for maintenance undervoltage protection circuits to remain energized for satisfactory operation control circuits for interlocking Excepted circuits require warning labels and statement in the maintenance manual 5 3 1 Disconnecting required for Collector bars Slip rings Flexible cables On board
29. means to this end 35 Can just replace my MCR with a safety relay No Simply replacing the MCR with a safety relay does not directly correlate with making the machine comply with the Machinery Directive The safety relay must be applied according the relevant directives and standards 36 37 38 39 40 41 How do safety interlock switches interface with a safety relay Are they an input to the relay or are they a load A safety interlock interfaces the same way an E Stop button interfaces as an input to the relay In some applications the interlock contacts will be wired in series with the E Stop Can use a standard magnetic switch It depends on the application Provided that its function and design meets the performance level indicated by the risk analysis manufacturers can select any component they like In which application should use safety controls An application should use the type of controls needed to make the application as safe as reasonably possible Whether you use safety controls or not skirts the core issue which is to understand what the machine s risks are and design the machine and its controls accordingly Do I have to use a safety relay in conjunction with every electrical safety device e g Safety interlock switch light curtain safety mat E Stop etc Not necessarily as it depends on the application and the control system The risk associated with your machine mig
30. p HE ba S i JBI SD O wer ki sGnED Soa as Negative Mode Positive Mode Machine operating guard closed Machine stopped guard open Fig 5 4 Limit switches operating in combined mode 5 6 Normally energized circuits A well proven principle for safety circuits is to make them function when the electric supply is interrupted e g loose connections wire breakage brown out etc Normally energized circuits detect power loss and ensure that the safety function remains intact Examples of these types of circuits are electrically operated brakes emergency stop circuits and the output relays of electronic motor protection relays By executing the safety function i e removing power after detecting a single fault normally energized circuits can help fulfill Category 2 and 3 safety requirements Devices such as E Stops limit switches safety gate interlock Cable pull safety switch switches and cable pull safety switches use direct opening action principles which is required under EN 60947 5 1 These well tried components are used in control systems with performance requirements from category B to 4 Safety gate interlock switch Limit switch lead a Safety relays use positively driven contacts to help prevent the simultaneous closure of NO and NC contacts which is required under EN 60947 5 1 These well tried components are most often used in control systems meeting category 3 and 4 requirement
31. priority over the start controls Once the machinery or its dangerous parts have stopped the energy supply to the actuators concerned must be cut off Stopping device Emergency stop Each machine must be fitted with one or more emergency stop devices to enable actual or impending danger to be averted The stopping device must have clearly identifiable clearly visible and quickly accessible controls stop the dangerous process as quickly as possible without creating additional hazards where necessary trigger or permit the triggering of certain safeguard movements The stop command must be sustained by engagement of the emergency stop device until that engagement is specifically overridden it must not be possible to engage the device without triggering a stop command it must be possible to disengage the device only by an appropriate operation and disengaging the device must not restart the machinery but only permit restarting 1 2 5 Mode selection 1 2 6 Failure of the power supply The interruption re establishment after an interruption or fluctuation in whatever manner of the power supply to the machinery must not lead to a dangerous situation In particular the machinery must not start unexpectedly the machinery must not be prevented from stopping if the command has already been given the protection devices must remain fully effective 1 2 7 Failure of the control circuit A fault in the control circuit l
32. required see Notes and 2 Note 1 It is believed at present that it is difficult to determine with any degree of certainty in situations when a significant hazard can occur due to the malfunction of the control system that reliance on correct operation of a single channel of programmable electronic equipment can be assured Until such time that this situation can be resolved it is inadvisable to rely on the correct operation of a single channel device according to 11 3 4 of EN 60204 1 Note 2 A proposed international standard IEC 1508 may provide more guidelines for the functional safety of programmable electronic systems when such systems are used as safety related systems To facilitate the design process Annex A of EN 954 lists some important aspects to consider during the design process These are 1 What reaction is required from the safety related parts of the control systems s when faults occur a No special action required b Safe reaction required within a certain time c Safe reaction immediately required 2 In which safety related part s of the control system should faults be assumed a Only in those parts in which by experience faults occur relatively often e g in the peripheral sensors and wiring b In auxiliary parts c In all safety related parts 3 Have both random and systematic faults been considered 4 Which faults should be assumed in the components of the safety related parts
33. to operate as intended The apparatus has an adequate level of intrinsic immunity to electromagnetic disturbance to enable it to operate as intended Most products that make use of electrical energy generate or are susceptible to electromagnetic fields Annex III of the EMC Directive states that electromagnetic disturbance generated by a product should especially not hinder apparatus such as industrial manufacturing equipment mobile radio equipment telecommunications networks and apparatus information technology equipment domestic appliances and lights and fluorescent lamps Though not called out in the directive be especially aware of the effects of motors and electric drives crosstalk between power cables and inadequate or improper grounding 3 4 The Low Voltage Directive This directive applies to equipment where the risks are mainly electrical in origin It covers equipment including components and assemblies which operate at 50 1000V AC or 75 1500V DC The Low Voltage Directive states that when installed and operated as intended equipment of this type must not endanger the safety of persons domestic animals or property Designers should review Annex I of the Low Voltage Directive which sets out principle safety objectives The Product Liability Directive This directive which addresses liability for defective products states that the injured persons shall be required to prove the damage the de
34. to survive frequent handling by the user It may be useful to mark them keep for future reference i A Technical File is the principle means of assessing conformity Only national authorities of an EU EAA country have the right to see it 4 3 Generate Technical File The Technical File Before drawing up the EC declaration of conformity the machine builder must ensure that certain technical documentation is available for inspection purposes This documentation is called a Technical File TF and it is a principle means of assessing product conformity The TF must contain the following A An overall drawing of the subject equipment B Full detailed drawings accompanied by any calculations notes test results etc required to check the conformity of the equipment with the EHSRs A list of the essential requirements of the Machinery Directive standards and other technical specifications which were followed when the equipment was designed D A description of methods adopted to eliminate hazards presented by the equipment If essential any technical report or certificate obtained from a competent testing body or laboratory Any technical report giving the results of tests carried out internally by oe engineering or others Documentation and test reports on any research or tests on components assemblies and or the complete product to determine and demonstra
35. up of electromagnetic elements e g contactors relays magnetic valves non starting or non stopping of motors e g servo motors mechanical blocking of moving elements loosening or displacing of fixed elements e g position switches drift beyond the tolerance values for analogue elements e g resistors capacitors transistors oscillation of unstable output signals in integrated components loss of entire function or of partial functions worst case behavior in complex integrated components e g microprocessors programmable electronic systems application specific integrated circuits Hydraulic and pneumatic components no switching or incomplete switching of the moving element e g sticking of a valve piston drift in the original control position of the moving element e g directional control valves leakage and modification of the leakage volume flow e g directional control valves unstable control characteristics in servo valves and proportional valves loss of pressure or bursting of lines e g of hose pipes and at the hose coupling clogging of the filter element in particular caused by solid substances ie abnormal pressure and or volume flow e g hydraulic pumps hydraulic motors compressors cylinders failure or abnormal modification of the input or output signal characteristics in sensors e g pressure switches Mechanical components spring fracture stiffness or sticking of
36. 1088 Interlocking devices w amp w o guard locking EN 982 983 Fluid power systems EN 294 349 811 Safety distances EN 999 Hand arm speed EN 626 Hazardous substances EN 1093 Emission of hazardous substances from machines EN 1127 1 Fire and explosions this work is now part of CEN TC 310 EN 1760 2 Pressure sensitive protective devices mats bumpers edges etc Electrical EN 60204 1 Basic electrical requirements IEC 1131 Programmable controllers IEC CD 1508 EN 418 EN 574 EN 50100 EN 61310 50099 EN 60947 EN 60947 5 2 104 Safety related systems electrical electronics programmable electronics Emergency stop equipment Two hand control devices Electrosensitive protective equipment Visual tactile and audible signals Low voltage switch gear and control gear Part 1 General rules Part 2 Circuit breakers Part 3 Switches disconnectors switch disconnectors and fuse combination units Part 4 Contactors and motor starters Part 5 Control circuit devices and switching elements Part 6 Multiple function equipment Part 7 Ancillary equipment Proximity devices Ergonomics EN 614 1 Ergonomic design principles terminology amp general principles EN 547 Human body dimensions EN 563 Temperature of touchable surfaces EN 894 Ergonomic requirements for the design of displays amp control actuators EN 981 System of danger and non danger signals with sound am
37. 3 23 EEC and the Product Liability PL Directive 85 374 EEC There are also directives for batteries explosive atmospheres simple pressure vessels personal protection equipment and dangerous substances Interpreting the Machinery Directive To clarify the Machinery Directive the F d ration Europ ene de la Manutention FEM a federation of manufacturers has produced a document which quotes the directive provides valuable comments and lists notified bodies This document is titled Interpreting the machinery directive and affixing the CE mark To order contact FEM at Kirchenweg 4 CH 8032 Z rich Switzerland Phone 011 41 1 384 48 44 Fax 011 41 1 384 48 48 Contents of the Machinery Directive Foreword Introduction Recitals Article 1 Article 2 Article 3 Article 4 Article 5 Article 6 Article 7 Article 8 Article 9 Article 10 Article 11 Article 12 Article 13 Article 14 Annex Essential Health and Safety Requirements Annex ll Contents of the EC declaration of conformity Annex lll CE marking replaced by 93 68 EEC Annex IV Types of machinery and safety components for which the procedures in article 8 must be applied Annex V EC declaration of conformity Annex VI EC type examination Annex VII Minimum criteria to be taken into account by member states for the notification of bodies Glossary of terms Summary of Machinery Directive The EC Machinery Directive 89
38. 4 Identification of other conductors power circuits black a c control circuits red d c control circuits blue 14 3 Wiring inside the enclosure conductors supported non metallic channels flame retardant door mounted devices wired with flexible conductors 14 4 Wiring outside the enclosure 123 i 124 204 1 Ref Description of Standards 14 4 1 IP protection at the wiring entrance is not reduced 14 4 2 External ducts see standard 14 4 3 Connection to moving elements of the machine see standard 14 4 5 Plug socket combinations Male plug on the load side Over 16 A retaining type Over 63 A interlocked with a switch type If more than one each identified by marking For control circuits no domestic type 14 4 6 Dismantling for shipment Terminals or plug sockets required at sectional points 14 5 Ducts connection boxes and other boxes 14 5 1 IP 33 protection minimum drain holes 6 mm dia allowed 14 5 3 Rigid metal conduit and fittings see standard 14 5 4 Flexible metal conduit and fittings see standard 14 5 5 Flexible non metal conduit and fittings see standard 14 5 6 Cable trunking systems see standard 14 5 7 Machine compartments and cable trunking systems see standard 14 5 8 Connection boxes and other boxes see standard 14 5 9 Motor connection boxes shal
39. 7 2 Overcurrent protection 7 2 2 Supply conductors provided or requirements are in the installation instructions 7 2 3 Power circuits per 7 2 10 Neutral conductor same as phase conductors no protection required Neutral conductors smaller than phase conductors see 473 3 2 1 of IEC 364 4 473 7 2 4 Control circuits Directly connected to the supply see 7 2 3 Supplied through a transformer required in the non earthed conductor 7 2 5 Conductors feeding outlets all non earthed conductors must be protected 7 2 6 Lighting circuits all non earthed conductors must be protected separately from other circuits 204 1 Ref Description of Standards Applicable Applicable Approved 7 2 7 Transformers protected per IEC 76 5 and IEC 742 7 2 8 Overcurrent protective devices are located where the conductor is connected to the supply 7 2 9 Short circuit rating is equal with the available sho
40. 8 5 Bonding to a common earth terminal is permitted for creating a noiseless earth identified by 417 IEC 5018 8 6 To reduce electrical disturbances low resistance may be used to PE connection marked with 417 IEC 5020 Control circuit supply shall be a separate winding transformer except for a single motor starters with two external control Control circuit voltage 277 V max when supplied by a transformer 9 1 3 Control circuit protection per 7 2 4 and 7 2 10 9 1 4 In one side earthed control circuits the control circuit switching devices connected in the live circuit except overload relay contacts and control devices in the same enclosure when earth fault is unlikely 9 2 2 Stop functions Category 0 uncontrolled stop see 3 62 Category 1 controlled stop see 3 12 power available during the stopping process 204 1 Ref 9 2 2 Description of Standards Category 2 controlled stop power is available after the stopping process Applicable Applicable Approved 9 2 3 Operating modes when more than one and hazard may result mode selector with lock may be required 9 2 4 Suspension of safeguards mode se
41. EC type examination Machinery 1 O o N BD Circular saws single or multi blade for working with wood and analogous materials or for working with meat and analogous materials A Sawing machines with fixed tool during operation having a fixed bed with manual feed of the workpiece or with a demountable power feed B Sawing machines with fixed tool during operation having a manually operated reciprocating saw bench or carriage C Sawing machines with fixed tool during operation having a built in mechanical feed device for the workpieces with manual loading and or unloading D Sawing machines with movable tool during operation with a mechanical feed device and manual loading and or unloading Hand fed surface planing machines for woodworking Thickeners for one side dressing with manual loading and or unloading for woodworking Band saws with a fixed or mobile bed and band saws with a mobile carriage with manual loading and or unloading for working with wood and analogous materials or for working with meat and analogous materials Combined machines of the types referred to in 1 to 4 and 7 for working with wood and analogous materials Hand fed tenoning machines with several tool holders for woodworking Hand fed vertical spindle moulding machines for working with wood and analogous materials Portable chain saws for woodworking Presses including press brakes for the cold working of me
42. ENELEC CERTIFICATE OF ADEQUACY The type of certificate issued when a Notified Body determines that the applicable national standards have been correctly applied to the design and manufacture of the machinery under review COUNCIL OF THE EUROPEAN COMMUNITIES The legislative body of the EU DECLARATION OF CONFORMITY A formal signed statement indicating conformity of the referenced product to the listed provisions of the applicable directive s Entitles manufacturer to affix CE Marking DIRECTIVE Legislation which is binding on all Member States that has been adopted by the Council of the European Communities EC TYPE EXAMINATION The procedure by which a notified Body ascertains and certifies that an example sample of machinery satisfies the provisions of the applicable directive s ESSENTIAL HEALTH AND SAFETY REQUIREMENTS EHSRs To comply with the Machinery Directive machinery must satisfy the essential health and safety requirements set out in Annex I The requirements are wide ranging and take into account potential dangers to operators and other exposed persons within a danger zone Aspects covered in Part 1 include the materials used in the construction of the machinery lighting controls stability fire noise vibration radiation emission of dust gases etc maintenance and instruction handbooks Part 2 has additional requirements for agri foodstuffs machinery portable hand held machinery and machinery f
43. Insulating barrier Starter coil Fig 6 1 Safe separation between main and logic circuits PELV SELYV allows technicians to work on 24V circuits e g PLC circuits without needing protective measures against electric shock Thus control circuit devices e g contactor coils and auxiliary contacts operating in PELV SELYV circuits require a higher level of physical separation between the main circuits and the control circuits see Figure 6 2 This can be achieved by reinforced insulation The safe separation of circuits must be maintained under all conditions Devices with safe separation preclude the need for interposing relays and contribute to a lower cost control system Insulating barrier Fig 6 2 PELV and SELV contactors provide safe separation between circuits 6 5 Protection against electric shock EN 60204 1 standard requires that persons are protected against electric shock from direct contact and indirect contact Protection against direct contact can be accomplished by placing the electrical equipment in a proper enclosure The standard indicates three ways to achieve protection e The enclosure can only be opened with a key or tool or e The door is interlocked with the disconnector or e All live parts are protected to IP2X or IPXXB Key or tool opened This assumes that only qualified persons will open an enclosure containing live electrical equipment The person doing so must follow the proper safety procedur
44. N 292 2 provides an overview of the technical principles and specifications for incorporating safety into a machine e g avoiding or reducing as many of the hazards as possible by using the most suitable design features and by limiting a person s exposure to hazards by reducing the need for operator presence intervention in danger zones EN 292 2 addresses risk reduction by design safeguarding see Figure 3 2 creating information for use i e an owner s manual and additional precautions designers can take related to improving safety Hopefully just the brief information and charts referenced here have convinced manufacturers that the standards establish a helpful framework for designing safe machines HAZARDS GENERATED BY MOVING TRANSMISSION PARTS fixed guards see 4 2 2 2 or interlocking guards with or without guard locking see 4 2 2 3a HAZARDS GENERATED BY MOVING PARTS CONTRIBUTING TO THE WORK DIRECTLY INVOLVED IN THE PROCESS AS e g TOOLS Can they be made completely inaccessible while working fixed guards see 4 2 2 2 or interlocking guards with or without guard locking with automatic monitoring see 4 2 2 3b or safety devices see 4 2 3 selected according to the need for access to the danger zone see 4 1 2 and 4 1 3 fixed guards see 4 2 2 2 preventing access to the moving parts in the zones away from the process and adjustable
45. R MACHINE INTERFACE SEEING MANUAL CONTROLS DISPLAY ACTUATORS WARNING CONTROL DEVICES CONTROL DATA STORAGE SYSTEM AND LOGIC OR ANALOG DATA PROCESSING OPERAT MAC SENSORS INTERFACE SAFETY DEVICES POWER CONTRO ELEMENTS contactors valves speed controllers etc MACHINE ACTUATORS engines cylinders ER TRANSMISSION ELEMENTS WORKING PARTS GUARDS OPERATOR MACHINE INTERFACE Fig 1 0 General schematic representation of a machine from EN 292 1 Annex A According to the Machinery Directive only companies building a machine for the EU market need to apply CE marking Many individual components and sub assemblies such as those having no independent source of energy or those that are not safety components may not need marking at all or they may be CE marked according to other directives 1 3 Good intentions The overall charge of the Machinery Directive explains that Member states are responsible for ensuring the health and safety of workers notably in relation to the risks arising out of the use of machinery The social cost of the large number of accidents caused directly by the use of machinery can be reduced by inherently safe design and construction of machinery and by proper installations and maintenance Further the directive mandates a common sense approach for addressing safety e g Each machine must be
46. Start button welded fault If the start button is welded i e held energized prior to rearming of the system via the E Stop coil CR2 will not energize because the circuit is never complete in the rung with CR3 a and CR1 b If coil CR2 cannot energize it is not possible to pull in coil CR3 because CR2 c will not close Output CR2 d welded fault After rearming the system via the E Stop power flows and picks up coil CR2 The welded contact CR2 d will attempt to change state If the weld does not break the NO contact of CR2 c will not close thus coil CR3 cannot energize and the system cannot be started again Likewise if CR1 d welds CR1 b will be held open If CR3 c welds CR3 a will be held open Both situations prevent coil CR2 from energizing so the system cannot be rearmed E Stop failure If the lower E Stop fails one contact remakes and one does not or the spanner breaks coil CR3 will not energize If the upper E Stop fails coils CR2 and CR1 will not energize Machine designers can use safety relays to help safeguard human interaction with dangerous equipment As such circuits for operator interfaces palm buttons pull cords light curtains and similar devices are tied into the safety relay circuit One classic example of a machine requiring category 4 safety precautions is a large hand fed metal stamping press To ensure that the operator s body and hands are out of the hazard area during operatio
47. The risk associated with a particular situation or process is derived from a combination of the severity of harm and the probability of occurrence of that harm Probability of occurrence involves the frequency and duration of exposure probability of the event occurring and probability of avoiding or limiting the harm Based on risk level Annex B of EN 954 provides a decision tree a machine can be required to have control systems that meet the requirements of a particular safety category RISK REDUCTION Manufacturers must apply the following principles when designing a machine eliminate or reduce risks as far as possible take the necessary protection measures in relation to risks that cannot be eliminated and inform users of the residual risks due to any shortcomings of the protection measures indicate whether any particular training is required and specify any need to provide personal protection equipment SAFETY COMPONENT A component provided that it is not interchangeable equipment which the manufacturer or his authorized representative established in the Community places on the market to fulfill a safety function when in use and the failure of which endangers the safety or health of exposed persons i e not standard components Safety components shall not carry CE marking for complying with the Machinery Directive other directives may apply SELF CERTIFICATION A procedure whereby the manufacturer or its designated representative
48. Understanding the Machinery Directive eo A Road Map to CE Marking and Safety Related Control Product Applications Biscay tit Biba nO Pa Seer ts Pyreaeneas Sebastian poORRA en Jarague r pe n Granada Forala cuk maa fo igs OA Rockwell Automation Allen Bradley Understanding the Machinery Directive A Road Map to CE Marking and Safety Related Control Product Applications Important notice This publication contains summary information regarding European Union EU directives relevant to industrial control and automation products of the type manufactured by Rockwell Automation Allen Bradley This information is solely based on Rockwell Automation s interpretation of those directives and should not be considered a definitive analysis of all relevant EU directives or their impact on any one company s goods or services Because of the vast variety of product uses those responsible for the application and use of those products within the EU should conduct their own independent evaluation to assure that each application and use meets the requirements of all relevant directives as well as other local and regional codes laws and regulations Credits Rockwell Automation would like to extend special appreciation to the following individuals for sharing their knowledge of European safety legislation John Bloodgood Timothy Panchot President Sales representative JFB Enterprises Intertek Testi
49. able and pendant control stations shall be shock and vibration resistant 120 204 1 Ref Description of Standards Applicable Applicable Approved 10 2 Push buttons 10 2 1 Colors per Table 2 10 2 2 Markings IEC 417 symbols 5007 5008 5010 or 5011 10 3 2 Indicator lights colors per Table 3 10 3 3 Flashing lights allowed 10 4 Illuminated push buttons color coded per Tables 2 and 3 10 5 Rotary control devices mounted to prevent rotation of the stationary member 10 6 Start devices minimize inadvertent operation 10 7 Devices for emergency stop 10 7 1 Located at each control station and readily accessible 10 7 2 Types push button pull cord pedal operated no guard disconnect switch positive direct LJ operation per IEC 947 5 1 and self latching 10 7 3 Restoration of normal function after emergency stop only after manual reset 10 7 4 Actuators colored red background yellow push button mushroom type 10 7 5 Disconnect may be used when it is readily accessible and it is according to 5 3 2 type a b or c red operator yellow background 10 8 Devices for emergency swi
50. an fulfill category B requirements E Stop Stop Gate Interlock Pusher Controls l Fig 5 7 This control circuit can fulfill category 1 requirements NOTE These diagrams conform to NEMA style For an IEC version please refer to Appendix H 67 it has been applied properly Further assuming the E Stop is of the direct opening action type its normal failure mode is in the open circuit mode If the contacts are tack welded shut they should be forced open on actuation removing power Although the conventional relay illustrated in figure 5 6 has no open circuit failure mode reputable manufacturers produce relays that tend to operate reliably experience indicates that they rarely weld in the closed state If the risk assessment is low say a slow moving conveyor using a conventional relay may be acceptable If the risk assessment indicates category 1 perhaps the operator needs to be shielded from an arm pushing products onto the conveyor the designer must take additional precautions Such precautions could include a moveable guard which would use a gate interlock switch and three wire control i e an auxiliary holding contact Figure 5 7 shows a circuit diagram for incorporating a gate interlock and three wire control The safety interlock removes power from the system when the guard is opened disabling the pusher arm The three wire control is designed so that after a power loss the start
51. arly shown to contain electrical equipment use black lighting flash on yellow background per 417 IEC 5036 17 3 Functional identification control devices indicators displays marked per IEC 417 and ISO 7000 17 4 Marking of control equipment Supplier s name or trademark Certification mark Serial number if applicable 125 126 204 1 Ref 17 4 Description of Standards Voltage phases frequency full load current Applicable Applicable Approved Short circuit rating Electrical diagram number 17 5 Item designation not applicable to a single motor controller All components identified with the same designation as on the drawing 18 Technical documentation 18 1 Installation operation and maintenance information supplied in an agreed language see Annex B 18 2 Information to be provided see standard 18 3 Requirements applicable to all documentation per IEC 750 and IEC 1082 1 18 4 Basic information minimum information Electrical supply requirement Handling transportation and storage Inappropriate use of the equipment
52. armonized standards they choose to use to show conformity What relationships are there between EU directives and CE marking The directives state the EU law while CE marking indicates that the product meets the directives applicable to it To find out which directives apply to a product examine its Declaration of Conformity DOC Are directive requirements equivalent to UL standards No Directives are laws of the European Community where UL standards are standards put forth by a company What are harmonized and national standards How do they impact my efforts to be compliant with the EU directives The European Norms are harmonized standards which means that they are applicable in and recognized by all EU countries Showing conformity with harmonized standards is considered the easiest way to demonstrate compliance with the EU directives National standards are standards within a country that are singular to that country and they may differ from the harmonized standards National standards have no impact on complying with the EU directives What is the relationship between the Machinery Directive and OSHA requirements for safety Does having one mean you comply with the other The EU directives and OSHA requirements are independent of one another so having one does not mean that you comply with the other If you want to sell your machine in both the EU and the U S you need to understand both sets of require
53. ategory 2 Any check of safety functions which can be automatic or manual shall either 1 allow operation if no faults are detected or 2 generate an output which initiates control action if a fault is detected When possible this output shall initiate a safe state e g prevent starting restarting if the safety function is not available When not possible the output shall provide a warning of the hazard In some cases category 2 does not apply because checking cannot be applied to all components e g a pressure switch or temperature sensor Category 3 Typical examples of feasible measures for fault detection are the connected movement of relay contacts i e positive guidance or monitoring of redundant electrical outputs Feasible means that fault detection measures and the extent of their implementation depends mainly on the consequence of a failure and the probability of the occurrence of that failure The technology used influences the possibilities for implementing fault detection Category 4 Fault review may be stopped when the probability of further faults occurring is sufficiently low The number of faults considered sufficiently low varies For example in the case of complex microprocessor circuits a large number of faults can exist Conversely in an electro hydraulic circuit two or three faults can be sufficient to initiate a safety action Fault review may be limite
54. aults must not lead to a loss of the safety function Thus a fault will not cause the loss of the safety function and there is an opportunity for repair before the next fault can occur There are a number of methods to satisfy category 4 requirements including interwiring three positively guided relays or using a safety relay A safety relay incorporates the same circuitry and three interwired relays but consolidates them in an integrated box design Both designs feature a redundant self monitoring circuit with positively guided normally energized relay contacts To achieve redundancy and self monitoring a safety relay see Figure 5 9 operates using the following principles Normal operation When the E stop is pulled up power flows through CR3 a and CR1 b energizing the coil CR2 When this coil is energized the NO contact CR2 c closes which energizes coil CR3 NO contact CR3 b closes and holds the coil CR3 energized At the same time CR2 a and CR2 b close CR2 b holds in the coil CR2 The device is now armed and ready When the operator pushes the start button power flows NO contact CR2 a closes and energizes coil CR1 CR1 a closes to hold in CR1 Then the NC contact CR1 b opens and disconnects power from coil CR2 The final state is coil CR1 on coil CR2 off and coil CR3 on This condition allows the contacts of the output line CR1 d CR2 d CR3 c to be closed and the load energized
55. cation and location nature and frequency of maintenance permissible environmental conditions etc Further it specifically discusses the location of information i e on the machine itself if the risk warrants signals and warning devices markings signs pictograms and written warnings and accompanying documents e g the instruction handbook 4 2 Advice for drafting information for use a The information for use must clearly relate to the specific model of machine b When information for use is being prepared the communication process see think use should be followed in order to achieve the maximum effect and should follow sequential operations The questions How and Why should be anticipated and the answers provided c Information for use must be as simple and as brief as possible and should be expressed in consistent terms and units with a clear explanation of unusual technical terms d When it is foreseen that a machine will be put to non professional use the instructions should be written in a form that is readily understood by the non professional users If personal protective equipment is required for the safe use of the machine clear advice should be given and this information must be prominently displayed at the point of sale e g on the packaging as well as on the machine e Documents giving instructions for use should be produced in durable form i e they should be able
56. ce level of their equipment it is mandatory that they read and understand the directives themselves When in doubt about requirements machine builders should refer to the directives and standards do not accept expert opinion as fact or as the only possible interpretation The role of third party inspectors also generates many questions The important things to remember are that most manufacturers can self certify the directives clearly cite the exceptions and that the EU EEA does not require machines or components to have additional safety marks e g the German GS or Danish Demko marks other than CE marking Sometimes machinery buyers request that suppliers meet requirements beyond those for CE marking such as internal company standards In such cases machinery buyers should specify the additional standards to which they want the product tested against or built and machine builders should clarify this with the customer up front 2 6 Applying components properly Confusion can arise when machine designers hear that using control components with CE marking means that their machine meets Machinery Directive requirements This is not true CE marking on a control component usually indicates compliance with the Low Voltage or Electromagnetic Compatibility Directive Machinery Directive requirements for control components are an entirely separate set of concerns A good analogy for U S audiences might be this us
57. ction 2 3 of this handbook provides sources for purchasing the directives and standards Can use Rockwell Automation to get my machine CE marked No Only a machine s manufacturer can apply CE marking to the machine A common misconception is that a Notified Body can CE mark a machine A Notified Body assesses whether the manufacturer has adequately satisfied the directives applied the standards appropriately taking the burden of proof off the manufacturer 18 19 20 21 22 23 24 What are the costs involved with complying with the Machinery Directive Theoretically there should be no additional manufacturing cost as safety is an integral component of the design process Realistically the directives require more documentation than most companies normally develop How do assess my risk category EN 1050 provides principles for risk assessment and examples of hazards Annex B of EN 954 provides a flow chart for assessing risk and assigning categories See chapter 3 of this handbook for more details How do know if my risk assessment is accurate How do know when I m done EN 292 1 and EN 292 2 discuss risk in great detail and Annex B of EN 1050 covers methods for analyzing hazards and estimating risk Figure 3 1 in this handbook depicts the strategy for selecting designed in safety measures and indicates when you should ask yourself Is safety adequate Isn t it easier to just make everything
58. ctives 32 When selecting components is the answer application dependent Do you need to apply components differently for different applications Yes Start by asking two questions What is the function of the entire assembly How are you applying the component to the assembly Next look to the directives and standards for guidance By way of example the stop button and related circuits for a copy machine differ greatly from the stop button and related circuits for a saw mill or a large compression molding machine 33 Do safety relays replace a master control relay Yes Safety relays replace a master control relay MCR because they provide functions an MCR cannot 34 Why are safety relays needed Strictly speaking machine builders need the function and performance capabilities of a safety relay not the product itself Safety relays are designed to eliminate the potential for a single contact to cause a failure that would not allow the system to shut down This function helps meet risk category 3 or 4 requirements detection of a single failure maintenance of the integrity of the E Stop function and prevention of a restart until the fault is cleared A safety relay is really a combination of several relays wired into a circuit that provides the safety functions noted above Remember the Machinery Directive does not require the use of any particular product it specifies function and performance requirements A safety relay is a
59. d the advanced technology resources of Rockwell Aa Worldwide representation q Argentina Australia Austria Bahrain Belgium Bolivia Brazil e Bulgaria Canada Chile China People s Republic of e Colombia Costa Rica Croatia Cyprus Czech Republic Denmark Dominican Republic e Ecuador Egypt El Salvador Finland France Germany Ghana Greece Guatemala Honduras Hong Kong Hungary Iceland India Indonesia Iran Ireland Israel Italy e Jamaica Japan Jordan Korea Kuwait e Lebanon Macau Malaysia Malta Mexico Morocco The Netherlands New Zealand Nigeria e Norway Oman e Pakistan e Panama Peru Philippines Poland Portugal Puerto Rico Qatar Romania Russia Saudi Arabia Singapore Slovakia Slovenia South Africa Republic of e Spain e Sweden Switzerland Taiwan Thailand Trinidad Tunisia Turkey United Arab Emirates United Kingdom United States Uruguay Venezuela Rockwell Automation Headquarters 1201 South Second Street Milwaukee WI 53204 USA Tel 1 414 382 2000 Fax 1 414 382 4444 Rockwell Automation European Headquarters SA NV avenue Herrmann Debroux 46 1160 Brussels Belgium Tel 32 2 663 06 00 Fax 32 2 663 06 40 Rockwell Automation Asia Pacific Headquarters 27 F Citicorp Centre 18 Whitfield Road Causeway Bay Hong Kong Tel 852 2887 4788 Fax 852 2508 1846 Publication SHB 900 September 1997
60. d to two faults in combination when the fault rates of the components are low AND the faults in combination are largely independent of each other AND the faults have to appear in a certain order to jeopardize the safety function When making purchasing decisions consider that well tried components help meet category 1 and higher requirements 3 11 Risk performance and selection To help further guide the designer on how to relate risk and anticipated performance when selecting a performance category consider three examples For the first example imagine a two hand control used in connection with a large power press Risk analysis has determined that if the two hand control fails it could initiate a power stroke resulting in amputation or death This extreme risk requires a high performance level for that part of the control system and in most cases dictates meeting category 4 requirements The second example is a two hand control used on a packaging machine where the possible severity of injury is not more than a severe cut or bruise with a low to medium probability of occurrence The minimum performance level for this medium risk would be lower than required for the large power press and meeting category 2 requirements would likely suffice and depending on design and product selection category 1 might be sufficient The third example is a simple machine used to stake on wire terminals Any injury that could occur is sli
61. ded by the user 18 5 additional sheets to be provided where necessary 26 For which of the following classes of persons is access to the interior of enclosures required during normal operation of the equipment Skilled persons Instructed persons 27 Are locks with removable keys to be provided for fastening doors or covers YES NO 28 If two hand control is to be provided state the type 109 Gi After the inquiry form has been completed and the risk assessment performed machine manufacturers should fill out the Electrical equipment checklist which follows the EN 60204 1 standard The checklist has three columns The Applicable and Not Applicable columns are filled out as a reminder that these sections of the standard apply to the machinery The Approved column is provided for checking After the control equipment is completed it provides a place for the inspectors or approving persons to check that the applicable sections of the standard were properly applied ELECTRICAL EQUIPMENT CHECKLIST based on EN 60204 1 For control panels with CE marking according to the Machinery Directive this checklist must be filled out by marking the Applicable and Not Applicable columns The purpose of the Approved column is that the item checked and it is according to the requirement during final inspection Customer Order No Cat No Abecos COPS File Date Enc Type Enc Dimensions
62. e faults safety critical and non safety critical as they occur 1 e high level of safety performance when it is not feasible to expect multiple independent faults to accumulate within the checking period Requirements of cat B and the use of well tried safety principles together with Assimilation of faults will not cause a loss of safety function the number of faults in accumulation to be considered is normally two but may be more depending on the application circumstances Detection of single faults in time to prevent the loss of safety function Foreseeable combinations of faults will not cause loss of safety functions Detection of single faults immediately No combinations of faults will cause loss of safety functions this is the ideal but rarely achieved in practice High level of safety performance NOTES 1 If as a consequence of a fault further faults occur all the linked faults shall be considered as a single fault 2 Common mode faults are regarded as a single fault 3 The occurrence at the same time of two independent faults is not considered Availability of standards test data etc Use of materials and components conforming to recognized standards etc Guide to the Categories for Safety Related Parts of Control Systems From EN 954 1 Factors affecting the degree of performance Typical techniques Validation methods Check specifications for con
63. e necessary such as emergency stop console for training of robots positioned so that their operation cannot cause additional risk designed or protected so that the desired effect where a risk is involved cannot occur without an intentional operation made so as to withstand foreseeable strain particular attention must be paid to emergency stop devices liable to be subjected to considerable strain 1 2 3 Starting It must be possible to start machinery only by voluntary actuation of a control provided for the purpose The same requirement applies when restarting the machinery after a stoppage whatever the cause when effecting a significant change in the operating conditions e g speed pressure etc unless such restarting or change in operating conditions is without risk to exposed persons Where machinery has several starting controls and the operators can therefore put each other in danger additional devices e g enabling devices or selectors allowing only one part of the starting mechanism to be actuated at any one time must be fitted to rule out such risks 1 2 4 Stopping device Normal stopping Each machine must be fitted with a control whereby the machine can be brought safely to a complete stop Each workstation must be fitted with a control to stop some or all of the moving parts of the machinery depending on the type of hazard so that the machinery is rendered safe The machinery s stop control must have
64. ee standard 204 1 Ref Description of Standards Applicable Applicable Approved 9 3 5 When reverse current breaking is used the motor starting in the opposite direction shall be prevented if hazard could result 9 4 Control functions in the event of failure see risk assessment 9 4 2 1 Use of proven circuit techniques and components 9 4 2 2 Provisions for redundancy 9 4 2 3 Use of diversity 9 4 2 4 Functional tests 9 4 3 1 Earth faults in the control circuit shall not cause starting hazardous motion and shall not prevent stopping 9 4 3 2 Voltage interruptions see 7 5 and memory loss shall not create hazard 9 4 3 3 Loss of circuit continuity in safety circuits shall not result in hazard 10 Operator interface and machine mounted control devices devices mounted outside or partially outside the control enclosure 10 1 2 Location and mounting Accessible for servicing and prevent damage Hand operated control above 0 6 m and reachable 10 1 3 Enclosure protection IP rating minimum IPXXD 10 1 4 Position sensors not damaged by overtravel for safety related functions direct acting or equivalent 10 1 5 Port
65. eee 6 6 6 0 Operational functions The European Norms provide both broad guidance and great detail on safety functions which are safety critical functions other that safety specific functions that is components which provide critical operational functions According to EN 60204 1 this includes products such as power supply disconnecting devices enclosures power circuits control circuits and motor overload protection Properly applying these devices according to EN 1037 helps assure proper start up prevent unexpected start up and isolate the machine from its energy supply to enable safe maintenance or other work As with the safety components discussed in chapter 5 there are numerous well tried design principles manufacturers should look for when selecting power related safety components Some of these principles are e Contact reliability e Multiple fault detection e Short circuit protection for safety e Safe separation of circuits for avoidance of electrical shock e Protection against electric shock finger proof e Protection against indirect contact Recall that the products discussed in the previous chapter provide safety specific functions e g the primary purpose of a cable pull switch is to serve as a safety stop device not as a routine stop button 6 1 Contact reliability Many control circuits operate at 24V DC levels which is common for PLC systems and other electric controls The contact
66. ent 143 Appendix H IEC Style Diagrams from Chapter 5 145 Introduction New laws impact equipment manufacturers and end users 4 22 4 5 1 0 A dlobaliroadimap i ner re ey ee te 1 1 Does the Machinery Directive apply to me hed Good intentions 2 ee eee eeeee 1 3 New laws impact equipment manufacturers and end users AS a prerequisite to participating in the global marketplace all machinery manufacturers and end users should consider machinery safety and control reliability when designing their equipment One significant force behind this international safety effort is the 1995 European law requiring all machinery built for use in the European Union EU and European Economic Area EEA to comply with the Machinery Directive on safety The law mandates that machine builders indicate compliance by placing CE marking on their machinery CE stands for Communat Europ ene which is French for European Community Though European in origin these safety related directives impact original equipment manufacturers OEMs end users and multi national corporations everywhere With components sourced from around the world the final destination and use of a product often remains unknown to its manufacturer Further companies producing machinery for Europe often turn to their suppliers for information and support as part of their effort to comply with the directives 1 1
67. ents Note While Type 2 and Type CPS allow component replacement the components eventually require replacing because short circuits cause heavy contact wear Correctly coordinated motor starters regardless of their type ensure that in case of a short circuit no damage occurs outside the starter This contributes to the protection of nearby personnel and control components In addition many circuit breakers and fuses for motor protection offer high current limiting capabilities to reduce fault energy to very low levels These lower energy levels reduce the danger to personnel and damage to surrounding equipment This enables short restart times particularly when short circuit coordination Type 2 or Type CPS is chosen Further devices with high current limitation do not require oversizing of the contact to achieve Type 2 or Type CPS coordination 6 4 Safe separation of circuits to avoid electrical shock PELV and SELV types of Extra Low Voltage operating on a maximum of 25V AC or 60V DC are used to avoid the hazard of electric shock The PELV SELV voltage is supplied from a source with an increased safety level such as from a safety isolating transformer where one side of the circuit is connected to protective earth All PELV SELV circuits must be separated from other circuits with the level of separation of a safety isolating transformer Safe separation between the power and the control circuit is shown in Figure 6 1
68. ernet site at www ab com Click on the Allen Bradley and the CE mark button Do the new MCS control relays including Adder Decks incorporate positively guided contacts Yes Glossary of Terms ANNEX An appendix as might be used with a Council Directive ANNEX IV EQUIPMENT Machine types which are considered to be particularly dangerous Also includes safety components Such equipment must undergo a more stringent conformity assessment procedure including an EC type examination by a third party AUTHORIZED REPRESENTATIVE Person appointed by the manufacturer to act on its behalf in carrying out certain tasks required by the directive which the manufacturer has delegated to the representative At this time the authorized representative must be established in the European community to be able to act on the manufacturer s behalf It can be advantageous to establish an authorized representative CE MARKING CE mark The identifying mark consisting of the letters CE that together with an EC Declaration of Conformity indicates conformity of the product to which it is affixed to the essential health and safety requirements of the relevant directive s Allows products to be sold anywhere in the EU CE Marking is mandatory for most products in the EU CE stands for European Community in French CEN CENELEC European Committee for Standardization CEN European Committee for Electrotechnical Standardization C
69. es such as disconnecting power to the enclosure before working on it Interlocked The enclosure door may be opened only after the disconnector handle is in the open position The disconnector must disconnect all electrical power to the enclosure The line side terminals of the disconnector must be protected from accidental touching which sometimes is stated as being finger proof IP2X or IPXXB level If the requirements above are not met i e the enclosure cover has a handle that anyone can open the live parts must be protected to IP2X or IPXXB level The explanation for these designations is in the IEC 529 standard Degrees of protection provided by enclosure A simple explanation for these requirements is that a test finger shall not touch live parts An alternate protection is completely enclosing all live parts in an insulating material In practice this is possible only if the enclosure contains just conductors 6 6 Protection against indirect contact This protection is required in the event of an insulation failure between live parts and exposed conductive parts of electrical equipment It can be accomplished by preventing hazardous touch voltage or automatic disconnection as noted in clause 6 3 or EN 60204 One choice for preventing hazardous touch voltage requires the use of circuit breakers or fuses to automatically disconnect the circuit in case of a short circuit Connecting of exposed conductive parts
70. ety of machinery Principles for risk assessment Two other fundamental standards address specific safety aspects i EN 60204 1 Safety of machinery Electrical equipment of machines Part 1 General requirements e EN 954 1 Safety of machinery Safety related parts of control systems Part 1 General principles for design These four standards comprise the base standards to show conformance to the Machinery Directive The machine designer embarking on the CE marking quest should begin by obtaining the full text of the four standards noted above and the Machinery Low Voltage and Electromagnetic Compatibility Directives 2 3 Sources for standards The following organizations and companies provide copies of the standards and directives as of September 1997 1 ANSI American National Standards Institute 11 West 42nd Street New York NY 10036 USA Phone 1 212 642 4900 Fax for ordering 1 212 302 1286 Fax general 1 212 398 0023 Internet www ansi org Comments Now accepts credit cards ANSI is also the source of IEC amp ISO standards CEN and CENELEC pre standards prEN 2 International Electrotechnical Commission IEC 3 rue de Varembe P O Box 131 CH 1211 Geneva 20 SWITZERLAND Phone 011 41 22 919 0211 Fax 011 41 22 919 0300 Internet www iec ch l 11 Comments Direct source of IEC standards Will accept credit cards as part of phone order 3 International Organization for Standardization
71. f control systems Man machine interface 3 6 6 1 2 2 clause 10 of EN 3 6 7 60204 1 EN 60447 Appendix F Sample DOCs Words printed in italics are instructions for the person drawing up this declaration and should be deleted in the actual text of this declaration this model is to be used for machinery which is not mentioned in Annex IV of Directive 89 392 EEC In case of Annex V machinery this model should be amended to account for the special conditions in Annex II of Directive 89 392 EEC EC DECLARATION OF CONFORMITY FOR MACHINERY Directive 89 392 EEC Annex II sub A Manufacturer business name Address Herewith declares that description of the machinery make type serial number etc is in conformity with the provision of the Machinery Directive Directive 89 392 EEC as amended and with national implementing legislation is in conformity with the provisions of the following other EEC directives only to be mentioned where appropriate and furthermore declares that the following parts clauses of harmonized standards have been applied only to be mentioned where appropriate the following parts clauses of national technical standards and specifications have been used only to be mentioned where appropriate place date but only optional 139 Signature full name and identification of the person empowered t
72. fect s and the causal relationship between the damage and the defect s The directive also states that a product is defective when it does not provide the safety a person is entitled to expect taking all circumstances into account Further a product shall not be considered defective for the sole reason that a newer product is subsequently put into circulation The Product Liability Directive sets forth circumstances under which a manufacturer shall not be liable e That he did not put the product into circulation e The defect which caused the damage did not exist at the time when the product was put into circulation e The product was not manufactured for sale for any form of distribution for economic purposes e The defect is due to compliance of the product with mandatory regulations e The state of scientific and technical knowledge at the time when the product was put into circulation was not such as to enable the detection of the defect In the case of a component used within a product the defect can be attributed to the design of the product or the instructions provided with the product Know EMC and LV Though not the focus of this book the EMC and Low Voltage Directives often impact machine design quite significantly Machine builders should thoroughly understand the requirements of these directives Examining Type A B and C standards 3 6 Examining Type A B and C Standard
73. fety requirements Do I need to use components with CE marking on them to meet Machinery Directive requirements This is an apples to oranges comparison CE marking on a component indicates compliance with an EU directive that applies to components such as the Electromagnetic Compatibility EMC Directive or Low Voltage LV Directive The Machinery Directive has requirements for controls and safety components e g must use positively guided contacts and these are an entirely separate set of concerns from the EMC and LV Directives What is the difference between the LV and EMC Directives The Low Voltage Directive covers electrical equipment between 50 1000V AC and 75 1500V DC The Electromagnetic Compatibility Directive covers electrical equipment which emits or is influenced by certain types of electromagnetic radiation 10 11 If all components in my control panel are CE marked is my machine automatically CE certified No absolutely not Component installation must be verified and there are other requirements that apply to the entire assembly For example using a safety relay with CE marking has nothing to do with whether you ve properly guarded against a dangerous motion Secondly there is no such thing as CE certified or CE approved Machine builders must comply with or show conformity to to the Machinery Directive any other directives that apply and any h
74. formity and suitability The simplicity or complexity of the system and principle i e fewer components means fewer potential modes of failure and more viable validation Positive mode operation life testing oriented failure Mode and Effects Analysis mode e g defined weak or Fault Tree Analysis link relevant to simple Testing e g mechanical equipment Validation measures are usually too involved or not possible for more complex e g electronic equipment e Fault analysis e g Failure e Checking of safety margins The frequency and nature of the check i e more frequent checks allows less time for faults to remain undetected Simulation of device actuation and functional check by machine control system or dedicated monitoring unit with start interlock Theoretical analysis and or testing The frequency and nature of the check i e more frequent checks allows less time for faults to accumulate Dual contact or two separate devices linked by two circuits to a separate unit which compares operation of each circuit at change of state Suitable where some faults cannot be prevented and there is relatively frequent actuation particularly relevant to electro mechanical technology Theoretical analysis and or testing The simplicity or complexity of the system and principle i e fewer or simple
75. g is per Table 5 13 5 Cable voltage drop less than 5 13 6 Smallest cross section per Table 6 Flexible cables see standard 13 7 i 13 8 Collector wires collector bars and slipring assemblies see standard 204 1 Ref 14 Description of Standards Wiring practices Applicable Applicable Approved 14 1 1 Terminal blocks identified Liquids drain away from flexible wires Crimp connections crimp conductor and insulation Wiring does not cross over terminal blocks 14 1 2 Conductors and cable runs Avoid splices from terminal to terminal Extra length for termination PE conductors routed with phase conductors 14 1 3 Conductors of different circuits may be in the conduit or cable insulation for the highest voltage in the group 14 2 Identification of conductors 14 2 1 Identified at each terminals for color coding see standard 14 2 2 Identification of PE conductor is green and yellow throughout the length of the conductor 14 2 3 Identification of the neutral conductors color light blue 14 2
76. g the emergency stop command shall also result in the latching in of the control device so that when the action on the actuator is discontinued the emergency stop command shall be maintained until the control device is reset unlatched These standards require IEC style E Stops to provide a means whereby the device s operator will never be in a latched in state without the normally closed contact opening Further if the contacts are welded or obstructed from opening the operator should not be allowed to latch By convention manufacturers have used a feature called trigger action to achieve this Trigger action describes an operator that has a point of no return in its travel after which the contacts move through their full stroke Some gate interlock switches also employ a similar point of no return feature and these interlocks are said to be of a snap acting design Redundancy Using devices with different operating principles or using more than one device to perform a control function increases circuit reliability This is called redundancy and it is a good design practice that can fulfill category 2 and 3 functions for the safety of control circuits Figure 5 4 shows a sliding guard which closes off gears Notice how it helps avoid failures of the same kind by combining a limit switch with a positive mode NC contact with a second limit switch that has a negative mode NO contact lt lt _ Moving guard
77. ght and the probability of that occurring is low A less sophisticated category 1 performance level might be acceptable The point of these examples is that it is probably not necessary to select a category 4 m performance level when the risk is low However even a well designed category 1 system probably cannot be expected to provide the required minimum performance level for high risk machinery Further do not assume that a well designed system meeting category 4 requirements provides adequate safety for a high risk situation Designers must make a risk evaluation and determine whether there is a need to provide other means of safeguarding e g fixed barriers 3 12 Summary By using EN 1050 and EN 954 the machine designers objective is to ensure that the safety related parts of a control system produce outputs which can achieve risk reduction objectives The process for selecting and designing safety measures takes five steps Step 1 Hazard analysis and risk assessment Identify the hazards present at the machine during all modes of operation and at each stage in the life of the machine by following the guidance in EN 292 1 and EN 1050 Assess the risk arising from those hazards and decide the appropriate risk reduction for that application in accordance with EN 292 1 and EN 1050 Step 2 Decide measures for risk reduction by control means Determine the design measures at the machine and or the provision of
78. gislation law that lays down the essential health and safety requirements applying to machinery as defined in Annex I It also covers safety components placed on the market separately MANUFACTURER Person responsible for designing and manufacturing a product covered by the directive s with a view to placing it on the community market The manufacturer is responsible for designing and manufacturing products in accordance with the directives 99 and following the certification procedures declaration type exam CE Marking and preparation of files MEMBER STATES Those nations that make up the EU 100 NOTIFIED BODY An independent testing laboratory that a Member State has determined to be qualified to perform testing and certification functions relating to specified EC Directives The Member State notifies the EC and the laboratory of the laboratory s qualified status as tester and certifier PERFORMANCE CATEGORIES EN 954 states that safety related parts of control systems shall be in accordance with the requirements of one or more of the five categories B 1 2 3 4 The categories state the behavior required of safety related parts of control systems with respect to its resistance to faults RISK ASSESSMENT or risk analysis From EN 1050 which establishes general principles and procedures for identifying hazards and evaluating risks as they relate to decisions made on the safety of machinery RISK ESTIMATION
79. hat machinery meets requirements of applicable sections of Annex en CE Marking Having developed the TF drawn up a DOC and if required passed an EC type examination the machinery manufacturer may now legally affix CE marking to its product CE marking consists of the symbol shown in Figure 4 If the marking is reduced or enlarged the proportions given in the drawing below must be maintained Usually the minimum vertical dimension may not be less than 5 mm but this may be waived for small scale machinery gt jet unit 1 unit je 7 units Soudoonccuscasessd fb soo oouoonSonsoged 1 S 17 units E Fig 4 0 CE marking symbol and its proportions Safety Category Requirements Why include safety and safety related components 5 0 Well tried components and design principles J l Direct opening action contacts 2 4 ne ee 5 2 RBositve ydmvenicontacts aae 53 Redundancy Creag seer arn N N A S OS A A ee an 5 4 Normally energizedicincunts me m S3 Chapters 1 through 4 of this handbook guided readers through the logistics of obtaining CE marking Now chapters 5 and 6 will provide information that shows readers how to select and apply control related products while considering requirements of the directives and standards Specifically chapter 5 focuses on the design of safety related control products as well as the safety categories introduced in section 3 10 Chapter 6 focuses on the electrica
80. her than electricity 1 5 4 Errors of fitting 1 5 5 Extreme temperatures 1 5 6 Fire 1 5 7 Explosion 1 5 8 Noise 1 5 9 Vibration 1 5 10 Radiation 133 134 1 5 11 1 5 12 1 5 13 1 5 14 1 5 15 External radiation Laser equipment Emissions of dust gases etc Risk of being trapped in a machine Risk of slipping tripping or falling 1 6 1 6 1 Machinery maintenance Maintenance It must be possible to carry out adjustment maintenance repair cleaning and servicing operations while machinery is at a standstill If one or more of the above conditions cannot be satisfied for technical reasons these operations must be possible without risk 1 6 2 Access to operating position and servicing points 1 6 3 Isolation of energy sources 1 6 4 Operator intervention 1 6 5 Cleaning of internal parts 1 7 Indicators warning marking instructions 1 7 0 Information devices 1 7 1 Warning devices 1 7 2 Warning of residual risks 1 7 3 Marking 1 7 4 Instructions Appendix D Some significant faults and failures Electrical electronic components short circuit or open circuit e g each fault short circuit to the protective conductor or a conductive part open circuit of any conductor short circuit or open circuit occurring in single components e g in position switches control and regulation equipment machine actuators relay contacts non drop out or non pick
81. ht not require a safety relay Also you may not have to use a separate safety relay with each input device For example a safety interlock switch light curtain and E Stop related to the same hazard may be wired in series to one safety relay If have redundant safety input devices does this eliminate the need for a safety relay No Redundancy does not deliver the same function as a safety relay What is the current OSHA ruling on safety relays and switches Just like the European directives and standards the OSHA requirements look to a certain level of performance for the control system It does not specify products By design a safety relay can help provide the performance OSHA seeks 42 43 44 45 What do positively guided and positive break mean and how do they differ Does Rockwell Automation offer products with these features Positively guided refers to the electronic actuation of relay contact auxiliary contact actuation on starters Positive break refers to the mechanical actuation of devices like an interlock switch or E stop button Chapter 5 of this book provides detail on their differences Rockwell Automation offers a variety of safety components employing these operating principles Can customers build their own safety relay using Rockwell Automation components and will it be approved Yes they can build their own safety relay using Rockwell Automation components or any other components
82. iagram of a redundant system When the start button is pushed under normal operating conditions current will flow through the NC contacts CR1 a and CR2 a energizing output coils CR1 and CR2 Then contacts CR1 b and CR2 b close and maintain current flow the NC contacts CR1 a and CR2 a drop out If one of the contacts welds during operation e g CR1 c it is still possible to remove power from the load using the E stop A restart would not be possible because the NC contact CR1 a would remain in an energized i e open state This fulfills category 2 requirements because the safety function is checked at the start of each cycle It also can fulfill some category 3 requirements because a single fault will not 69 cause the loss of the safety function E Stop Gate Interlock Start CR1 a CR2 a Robot E Stop CR1 c CR2 c Controls lp __ j Fig 5 8 This control circuit can fulfill category 2 requirements 5 10 Category 3 and category 4 As noted earlier category 3 requirements state that the safety function cannot be lost as the result of a single fault Where practical a category 3 system will detect a single fault but an accumulation of faults can lead to the loss of the safety function To satisfy category 4 requirements all previous requirements must be met plus a single fault must be detected at or before the next demand on the safety function If this is not possible then an accumulation of f
83. ic or failure of or damage to the control circuit must not lead to dangerous situations e Movable guards must be designed and incorporated into the control system so that moving parts cannot start up while they are within the operator s reach Conduct Risk Assessment and Risk Estimation Apply requirements of A amp B standards as needed 3 8 Risk assessment EN 1050 Risk assessment is a series of logical steps to enable in a systematic way the examination of hazards associated with machinery it is then followed when necessary by risk reduction j Repeating this process eliminates hazards and or implements safety measures as far as possible Refer back to Figure 3 1 for a schematic representing this strategy EN 1050 a Type A standard describes principles for a consistent systematic procedure for risk assessment and it gives guidance for making decisions during the design of machinery The five basic components or steps of EN 1050 are 1 Determination of the limits of the machinery Refer to EN 292 2 Hazard identification Refer to Annex A of EN 1050 for examples of hazards Annex B describes methods for the systematic analysis of hazards Failure Mode and Effects Analysis etc 3 Risk estimation described in detail in section 3 9 4 Risk evaluation determine if risk reduction is required or whether safety has been achieved If risk reduction is required reduce risk by design safeguardi
84. ing UL listed components for a panel does not mean the panel meets UL requirements To create a UL approved panel the components must be wired and installed according to an acceptable methodology the National Electric Codes This ensures that components are used for their intended function or conversely it helps to prevent unacceptable practices such as trying to run 200 amps through 16 gauge wire While component suppliers can specify application parameters and provide design advice it is the machinery builder who integrates the components as part of a machine Thus the builder must take responsibility for ensuring that the components have been assembled and applied in a manner that meets machine safety requirements MACHINERY e DIRECTIVE Machinery builders must apply control components in an appropriate manner to satisfy Machinery Directive requirements Remember Simply using components with CE marking does not mean your machine meets CE requirements IT Coup A LONG Z ey gee Without a road map the path to CE conformity can seem long and confusing The Road Map Starine OUt eE E Caen tet Wee ne enh a dare anaes 3 0 EN 292 Basic concepts of machine safety 3 1 We lt CITE CHIVES igor en ne etre Nee Rnd So ona 32 EMC Directives swine soos eee yee ae eee Jo Pielow Voltase Direc tye pe eee ee 3 4 Whe Product Liability Directive 2 cae ee 3 5 Examining Type A B and C Standards 3 6
85. into service until the machinery into which it is to be incorporated or of which it is to be a component has been found and declared to be in conformity with the provisions of Directive 89 392 EEC and with national 140 implementing legislation i e as a whole including the machinery referred to in this declaration place date but only optional Signature full name and identification of the person empowered to sign on behalf of the manufacturer DECLARATION BY THE MANUFACTURER variant 2 Directive 89 392 EEC Art 4 2 and Annex II sub B PROHIBITION TO PUT INTO SERVICE Manufacturer business name Address Herewith declares that description of the machinery make type serial number etc is intended to be incorporated into machinery or to be assembled with other machinery to constitute machinery covered by Directive 89 392 EEC as amended and that the following parts clauses of harmonized standards have been applied only to be mentioned where appropriate and that the following parts clauses of harmonized standards have been applied only to be mentioned where appropriate and furthermore declares that it is not allowed to put the machinery into service until the machinery into which it is to be incorporated or of which it is to be a component has been found and declared to be in conformity with the provisions of Directive 89 392 EEC and with national imple
86. ith communications capability fom ag teed Electronic overload relay provides Type 2 coordination when properly applied with the contactor shown on the facing page 83 Frequently Asked Questions FAQs Big Picture FAQs 1 What do the EU directives address Three basic areas 1 Safety of individuals 2 Protection of the environment and 3 Free movements of goods within the EU EEA geographical regions through harmonization of standards and the elimination of trade barriers Since these are European standards isn t it best to use European manufactured components No There are a significant number of non European manufactured products which comply with all aspects of European standards Further a larger variety and better products may be available if designers do not limit their selection to any one region Do I need to have a third party inspect my machine to obtain CE marking Most machinery manufacturers about 95 percent can self certify compliance with the Machinery Directives A few product categories i e high risk machinery like punch presses saws etc require third party certification However note that meeting EMC Directive requirements often involves a third party Do I need to buy components with additional safety on them besides CE marking e g the German GS safety mark or Danish Demko mark No Any product bearing CE marking is held out to meet EU sa
87. king amp DOC demonstrates conformity Coupled with CE marking the DOC indicates that a product complies with the Machinery Directive and all other directives which may apply Declaration of Incorporation This includes providing the same information noted above as well as a statement that the machinery must not be put into service until it is brought into full compliance or the machinery in which it is to be incorporated is brought into full compliance Manufacturers who offer components for the safety related parts of control systems must also draw up a DOC being sure to note the safety function intended if it is not obvious from the description Samples for all three types of DOCs are given in Appendix F Can you self certify 4 5 Can you self certify Roughly 95 percent of all manufacturers can self certify compliance with the directives and standards and affix CE marking without involving a third party i e a Notified Body To self declare manufacturers must be confident of conformity assessment procedures provide a TF make a DOC and affix CE marking The other five percent of manufacturers may have to follow a different procedure The z EU has identified certain types of high risk machinery such as presses and saws and certain safety components such as logic units and devices designed to detect persons for safety reasons and listed them in Annex IV of the Machinery Directive see Appendix G for
88. l safety of control components 5 0 Why include safety and safety related components Safety components are included in the Machinery Directive even though they do not fit the definition of machinery because there is an important relationship between safety components and machinery The definition of safety component is a component which the manufacturer or his authorized representative places on the market to fulfill a safety function when in use and the failure or malfunctioning of which endangers the safety or health of exposed persons Further clarifying this 4 component can be classified as a safety component only if 1 its omission can endanger the safety or health of a person and 2 the machine could function without them In other words to be a safety component the component must have a specific safety function rather than an operational one For example safety relays and two hand controls are safety components A machine could equally be operated by other types of components the safety relays and two hand controls as applied by the manufacturer specifically function to help prevent accidents Annex IV of the Machinery Directive requires third party certification for logic units such as safety relays and for electrosensitive devices designed to detect and safeguard persons such as light curtains However components generally used in the safety related parts of control systems such
89. l be used only for conductors going to the motor Applicable Applicable Approved 204 1 Ref Description of Standards Applicable Applicable Approved 15 Electric motors and associated equipment see standard 16 Accessories and lighting 16 1 Socket outlet per IEC 309 1 or marked with voltage and current Unearthed conductors protected for overcurrents 16 2 Local lighting of the machine and equipment 16 2 1 On off switch not in the lamp holder or in the cord 16 2 2 Supply voltage 50 V or less preferred not over 250 V isolating transformer may be required see standard 16 2 3 Protection per 7 2 6 16 2 4 Fittings lamp holders approved lamp protected if out of reach the section does not apply 17 Markings warning signs and item designations 17 1 Supplier s name or trade mark 17 2 Warning signs for enclosures not cle
90. lector with lock is required see standard 9 2 5 1 Protective interlocks see 9 3 prevent unintended movement in case of power supply fault battery replacement lost signal etc 9 2 5 2 Start possible after safeguards are in place Are hold to run controls required Correct sequential starting see 3 7 9 2 5 3 Stop see 9 2 2 function shall override the start function 9 2 5 4 2 Emergency stop Shall override all functions and operations Category 0 or 1 see risk assessment Category 0 only hard wired electromechanical components Category 1 final removal of power by electromechanical components 9 2 5 4 3 Emergency switching off see IEC 364 4 46 and Annex E 9 2 5 5 Monitoring of command actions hazardous conditions 9 2 5 7 Hold to run controls Two hand control see risk assessment Type 1 machine stops when either released wl 204 1 Ref Description of Standards Applicable Applicable Approved 9 2 5 7 Type 2 both must be released before machine can restarted Type 3 the control must be initiated within set time limit
91. list of harmonized standards followed and or solutions adopted to satisfy EHSRs operating instructions if any and a blueprint product plan if any The second part B would consist of a full file of all data Sign Declaration of Conformity The EC Declaration of Conformity DOC is the procedure by which manufacturers declare that the machinery being placed on the market complies with all the Essential Health and Safety Requirements EHSRs applying to it Signing the DOC authorizes the manufacturer to affix the CE marking to the machinery A copy of the DOC must accompany each product sold Contents of the DOC include A Name and address of the manufacturer B Description of the machinery C Where appropriate the name and address of the Notified Body and the number of the EC type examination certificate D Where appropriate the name and address of the Notified Body to which the file has been forwarded in accordance with Article 8 2 c of the Machinery Directive F Where appropriate a reference to the harmonized standards G Where appropriate the national technical standards and specifications used H Identification of the person empowered to sign on behalf of the manufacturer or his authorized representative s in the EU For components that will be incorporated into another machine and do not fully comply with the directives the manufacturer must make an EC CE mar
92. luation For each hazard related to a task or reasonably foreseeable misuse Validate results Is the risk Ye Are additional tolerable Ge hazards created Case where the supplier cannot reduce the risk to q a tolerable level and there fore must rely on the user 20 to provide additional safe guards or protective measures Can hazard be Can risk be eliminated by reduced by safe design guarding Provide warnings signs symbols as req d Finalize information for use Documentation More hazards Fig 3 1A Procedure for suppliers to assess and reduce risk from proposed update to EN 292 1 Information provided by the supplier as to proper use including limits residual risk additional protective measures safe working practices training Determine the application of the machinery or system Task identification Risk estimation New task added Risk evaluation For each task Validate results Is the risk tolerable Yes Additional safeguards guards protective devices protective measures personal protective equipment Develop safe working procedures Case where the supplier cannot reduce the risk to a a tolerable level and there Conduct training fore must rely on the user to provide additional safe guards or protective measures User requirements specific user or user community Fig 3 1B Procedure for users to assess and reduce risk from proposed update to EN 292 1 22 E
93. menting legislation i e as a whole including the machinery referred to in this declaration place date but only optional Signature full name and identification of the person empowered to sign on behalf of the manufacturer 141 F 142 EC DECLARATION OF CONFORMITY FOR SAFETY COMPONENTS PLACED ON THE MARKET SEPARATELY Directive 89 392 EEC Annex II sub C Manufacturer business name Address Herewith declares that description of the machinery make type serial number etc which has the following safety function if not already obvious from the description is in conformity with the provisions of the Machinery directive Directive 89 392 EEC as amended and with national implementing legislation is in conformity with the provisions of the following other EEC directives only to be mentioned where appropriate and furthermore declares that the following parts clauses of harmonized standards have been applied only to be mentioned where appropriate the following parts clauses of national technical standards and specifications have been used only to be mentioned where appropriate place date but only optional Signature full name and identification of the person empowered to sign on behalf of the manufacturer Appendix G Annex IV equipment The following types of machinery and safety components may require an
94. ments 12 13 14 15 16 17 Will the Machinery Directive ever displace OSHA or ANSI design guidelines No because the electrical codes and installation requirements differ between North America and Europe However they are getting closer over time Does CE marking or the DOC certify compliance with the no PCBs no asbestos requirement of Europe The use of asbestos is covered by one of the Marketing Directives and Use of Dangerous Substances Directive Where asbestos is used these directives apply These directives do not mandate CE marking but a machine bearing CE marking must meet their requirements What impact do the EU safety directives have on equipment built in and destined for the U S Legally the directives have no impact on the U S In practice however manufacturer s may try to build one piece of equipment that satisfies both EU and U S requirements to improve manufacturing efficiency How do self certify my machine to obtain CE marking Start with this safety handbook and follow the road map provided Obtain the directives and standards that apply to your machinery and thoroughly digest and apply them this point cannot be overstated Ultimately you must be able to prove if called upon to do so to an authorized body that you have met the Essential Health and Safety Requirements in Annex I of the Machinery Directive Where do get the necessary documentation related to CE marking my machine Se
95. ms for safe putting into service use handling assembly dismantling adjustment and maintenance and a repeat of information with which the machine is marked The Machinery Directive mandates that on being put into service instructions accompanying the machinery must be in the language s of the country in which the machinery is to be used this is in addition to instructions in the manufacturer s native language Further Directions and Safety Machine manufacturers should provide directions for safe and correct use of the machine The directions and information must not compensate for design deficiencies when manufacturers source components from other companies they must obtain all necessary instructions from suppliers and incorporate those instructions into their own instructions in a logical manner For example take the instructions for a piece of machinery using a DC motor with brushes Motor maintenance procedures and schedules should be included as an integral part of the entire machine s maintenance instructions Including a line such as Motor maintenance see accompanying motor manual and attaching the motor supplier s owner manual at the end of machinery instructions is generally not sufficient Clause 5 of EN 292 2 also details requirements for information for use It recommends that instructions contain information in basic areas e g modes for stopping the machine fault identifi
96. n the press uses two hand control for actuation To wire in the relays for the two hand control or cable pull switch light curtain etc put two NC contacts in the circuit just prior to CR3 a that is replace the jumper If one of the two relays welds in the energized position the safety relay will detect failure and prevent the machine from starting Note that the objective of the two hand control safety relay combination is not to detect a failure while the machine is running if something fails at this stage the operator will know it Rather if a single contact or an entire relay fails the multiple redundant relays in the load circuit are designed so that the load can be de energized and the self monitoring circuit prevents a restart until the fault is corrected Channel 1 Channel 2 Fig 5 9 This control circuit can meet category 4 requirements Note In order to minimize the potential for shorting of channel 1 to channel 2 which would not be detected by the circuit the wiring should be installed in separate conduits Safety Concerns for Power Related Products Operational Unc ionsiw g see eee cuee eae eae 6 0 Contacttchability eens Dee nee eon eerie 6 1 Multipletault detection eet ee 6 2 MOotonprotectio ntra ae re eens wre natn oe ee 6 3 Safe separation of circuits to avoid electrical shock 6 4 Protection against electric shock 22 7 2 2 6 5 Protection against indirect contact
97. n with or without supervision e Operation by experts or non professionals e Speed with which the hazard arises e Possibilities for avoiding the hazard reaction time third party intervention e Practical experience relating to the process e Probability that the harmful event will occur 3 10 Performance categories EN 954 Parts of machinery control systems both hardware and software are frequently assigned to provide safety functions A safety related part of the control system means a part or subpart s of a control system which responds to input signals and generates safety related output signals The combined safety related parts of a control system start at the points where the safety related signals are initiated and end at the output of the power control elements This also includes monitoring systems EN 954 a Type B1 standard provides requirements and guidance for designing the safety related parts of control systems It describes characteristics of safety functions and specifies performance categories but it does not specify which safety functions and which categories shall be used in a particular case Clause 6 2 of EN 954 states that designers should construct safety related parts of control systems to meet the requirements of one or more of five performance categories Figure 3 6 summarizes these requirements and the corresponding behavior expected of the safety function principles Further explanation of the category
98. ndards but the Type C standards may deviate from them where appropriate or necessary Verify test or inspect that machinery meets requirements of applicable sections of Annex 3 7 Annex Essential Health and Safety Requirements Before building a machine all designers must thoroughly familiarize themselves with the Essential Health and Safety Requirements EHSRs found in Annex I of the Machinery Directive This law states that Machinery must be so constructed that it is fitted for its function and can be adjusted and maintained without putting persons at risk when these operations are carried out under the conditions foreseen by the manufacturer The aim of measures taken must be to eliminate any risk of accident throughout the foreseeable lifetime of the machinery 55 including the phases of assembly and dismantling Annex I sets forth laws on e Controls reliability starting and stopping energy isolation control failures e Protection against mechanical hazards e Protection against other hazards electricity temperatures fire explosion tripping falling and others e Maintenance e Indicators warning marking instructions See Appendix C for a more complete listing of EHSRs Annex I epitomizes the EU s common sense approach to safety For example e After an interruption or fluctuation in the power supply the machinery must not start unexpectedly A fault in the control circuit log
99. ng Services Fond du Lac Wisconsin Lake Elmo Minnesota Numerous individuals from Rockwell Automation Allen Bradley also deserve credit for their contributions to this handbook Kyle Ahlfinger Paul Brown Scott Coleman Jeff Dickman Kimber Lynn Drake Larry Fischer Dave Fisher Frank Graninger Rick Green Dave Hagemeier John Haydu Joe Kann Mike Kent John Lewis Jerry McCarthy Sheri Rasmussen Greg Reynolds Jerry Rondorf Marv Schilt Chuck Schroeder The Brady Company Barbara Steinberger Dick Steinmetz Irene Timm Heinz Unterweger Tami Witt Steve Zimmermann Thank you everyone and best regards to safety conscious managers everywhere James J Jerschefske Project Manager Rockwell Automation Allen Bradley Chapter 1 Introduction 1 0 New laws impact equipment manufacturers and end users 0000 000s 2 LIA clobal roadmap e ee ea os aes Cee ee 3 1 2 Does the Machinery Directive apply tome 3 MEGO dinteni ons oe cee a oe ee ea es eo 5 Chapter 2 Acronyms Numbers Help 2 0 lhe Europeanimarke ta cn ce cctcae cae end en cane 8 2 1 So what directives should I examine 8 2 2 Standards to clarify directives 25 6 5 4e ce eas 10 23 Sources LOW SLANG ANS 2 15 ase ats teee ate ewes soe fee eee 11 2A RCE marking cece ar ere al Cine A ee 13 Zo winter pret aiOns May Waly coe eee ee 14 2 6 Applying components properly 14 Chapter 3 The Road Map
100. ng and or informing operators 5 Documentation demonstrate the procedure followed and results achieved 3 9 Risk estimation EN 1050 and EN 954 Since all machinery containing identified hazards presents a risk machine designers must be able to evaluate the risk In turn this will allow designers to employ appropriate levels of safety measures The risk associated with a particular situation or process can be represented in an equation where Risk Severity Probability Frequency Figure 3 5 gives guidance only it is not a substitute for meeting the standard for helping the designer to choose a category based on risk assessment Estimate the severity possible degree of harm by considering the e Severity of injury 1 Slight normally reversible injury or damage to health 2 Serious injury or damage to health normally irreversible including death Estimate the probability of harm occurring by considering the e Frequency and duration of exposure F1 Seldom to quite often and or short exposure time F2 Frequent to continuous and or long exposure time e Possibility to avoid or limit the harm P1 Possible under specific conditions P2 Scarcely possible When a hazardous situation occurs P1 should only be selected if there is a realistic chance of avoiding an accident or of significantly reducing its effect P2 should be selected if there is almost no chance of avoiding the hazard Category Starting point
101. now what 4 0 Informatlomior Use 2 2 2 2 ese Pee ek eee ee 4 1 Advice for drafting information for use 4 2 The Technical File 2 ere ere oe re ea etna 4 3 Declarationol Contormity 2225 ee eee 4 4 Cam yOurSe lt Cory vans ca oe yen a erent atten ane 4 5 4 0 So you ve complied with requirements now what After building a machine and verifying that it complies with the directives and standards manufacturers need to complete five more steps before affixing CE marking 1 Create information for use 2 Generate a Technical File 3 Submit a product sample to a Notified Body or learn if the product does not have to be submitted to a Notified Body 4 Create the Declaration of Conformity 5 Learn how to properly apply CE marking While much easier and quicker to absorb than the previous material it s downhill from here the post design and post construction portions of the directives are still law and importantly still contribute significantly to safety Create Information for use 4 1 Information for use Creating good information for use instructions for using the machinery contributes significantly to the safety of machinery Annex I clause 1 7 4 of the Machinery Directive states that all machinery must be accompanied by instructions that cover items such as the foreseen use of the machinery workstation s likely to be occupied instructions and diagra
102. o sign on behalf of the manufacturer Please note that this declaration must be drawn up in the same language as the original instructions see Annex 1 Section 1 7 4 b and must either be typewritten or handwritten in block capitals It must be accompanied by a translation in one of the official languages of the country in which the machinery is to be used This translation must be done in accordance with the same conditions as for the translation of the instructions DECLARATION BY THE MANUFACTURE Variant 1 Directive 89 392 EEC Art 4 2 and Annex II sub B PROHIBITION TO PUT INTO SERVICE Manufacturer business name Address Herewith declares that description of the machinery make type serial number etc is intended to be incorporated into machinery or to be assembled with other machinery to constitute machinery covered by Directive 89 392 EEC as amended does therefore not in every respect comply with the provisions of this directive does comply with the provisions of the following other EEC directives only to be mentioned where appropriate and that the following parts clauses of harmonized standards have been applied only to be mentioned where appropriate the following parts clauses of national technical standards and specifications have been used only to be mentioned where appropriate and furthermore declares that it is not allowed to put the machinery
103. of the control system a Faults only in components which are not well tried Well tried not in the sense of reliability but from the view of safety b Faults in all components 5 Has the correct reference category been selected as it relates to the requirement for detecting faults a Normal requirements for fault detection This means that all faults which can be detected with relatively simple methods should be detected b Strong requirements for fault detection This means that techniques should be used which enable most of the faults to be detected If this is not reasonably practical combinations of faults should be assumed fault accumulation 6 What shall be the next action of the control system if a fault has been detected a The machine should be brought to a predetermined state as required by the risk assessment b Further operation of the machine can be permitted until the fault is rectified c The indication of the fault s is sufficient e g warning signal by Visual Display Units VDU 7 What is necessary to meet the maintenance requirement a Provision of information about the effects of deviations from design specifications b Automatic indication of the need of maintenance c Setting of maintenance intervals d Setting of component life e Provision of diagnostic facilities and test points f Special precautions for safety during maintenance 8 What methods should be
104. ogic or failure of or damage to the control circuit must not lead to dangerous situations In particular the machinery must not start unexpectedly the machinery must not be prevented from stopping if the command has already been given no moving part of the machinery or piece held by the machinery must fall or be ejected 131 F 132 automatic or manual stopping of the moving parts wherever they may be must be unimpeded the protection devices must remain fully effective 1 2 8 Software 1 3 Protection against mechanical hazards 1 3 1 Stability 1 3 2 Risk of break up during operation 1 3 3 Risks due to falling or ejected objects 1 3 4 Risks due to surfaces edges or angles 1 3 5 Risks related to combined machinery 1 3 6 Risks relating to variations in the rotational speed of tools 1 3 7 Prevention of risks related to moving parts The moving parts of machinery must be designed built and laid out to avoid hazards or where hazards persist fixed with guards or protective devices in such a way as to prevent all risk of contact which could lead to accidents 1 3 8 Choice of protection against risks related to moving parts Guards or protection devices used to protect against the risks related to moving parts such as pulleys belts gears rack and pinions shafts etc must be selected on the basis of the type of risk Fixed or movable guards can be used movable guards should be used where frequent access i
105. on Central Secretariat rue de Stassart 35 B 1050 Brussels Belgium Phone 011 32 2 51 96 919 Fax 011 32 3 51 96 871 Eom CE marking When machinery manufacturers place CE marking Figure 2 0 on their product they are stating that the product complies with all applicable directives To affix CE marking to a product manufacturers must issue a Declaration of Conformity DOC This is a formal signed statement indicating conformity of the referenced product to the listed provisions of the applicable directive s and standards Most machine manufacturers about 95 percent can self certify their compliance with the Machinery Directive i e it is not mandatory to use an outside agency in most cases A few product categories including high risk machinery such as punch presses saws etc require third party certification by a Notified Body If the product is not manufactured in the EU EEA it may be advantageous for the machine builder to establish an authorized representative located within the EU EEA The authorized representative should be easily accessible have ready access to the DOC and be able to supply supporting information on request Fig 2 0 2 Interpretations may vary The language of the directives and standards permits a variety of interpretations This in turn has led to misinformation and confusion about what they really require Since machinery manufacturers have responsibility for the performan
106. or its function and can be adjusted and maintained without putting persons at risk when these operations are carried out under the conditions foreseen by the manufacturer The aim of measures taken must be to eliminate any risk of accident throughout the foreseeable lifetime of the machinery including the phases of assembly and dismantling even where risks of accident arise from foreseeable abnormal situations In selecting the most appropriate methods the manufacturer must apply the following principles in the order given eliminate or reduce risks as far as possible inherently safe machinery design and construction take the measures in relations to risks that cannot be eliminated inform users of the residual risks due to any shortcomings of the protection measures adopted indicate whether any particular training is required and specify any need to provide personal protection equipment c When designing and constructing machinery and when drafting the instructions the manufacturer must envisage not only the normal use of the machinery but also uses which could reasonably be expected The machinery must be designed to prevent abnormal use if such use would engender a risk In other cases the instructions must draw the user s attention to ways which experience has shown might occur in which the machinery should not be used d Under the intended conditions of use the discomfort fatigue and psychological stres
107. or working wood and analogous materials Part 3 deals with particular hazards associated with mobility Part 4 with those associated with lifting Part 5 those with underground working and Part 6 those associated with the lifting and moving of persons EUROPEAN NORM EN also called a HARMONIZED EUROPEAN COMMUNITY STANDARD Voluntary guidelines not laws that clarify and expand on the essential requirements of the directives Standards provide the most expedient means of testing or verifying conformity to a directive They are developed by CEN and CENELEC These organizations have pledged to use international standards ISO and IEC whenever possible Harmonized standards supersede individual country requirements EUROPEAN UNION EU The regional geographic and economic union formed by 15 European nations bound by treaty to form a single European Economic Community The countries are as of January 1 1997 Austria Belgium Denmark Finland France Germany Greece Ireland Italy Luxembourg Netherlands Portugal Spain Sweden and the United Kingdom HAZARD An event that can cause physical injury and or damage to health or property Annex A of EN 1050 provides examples of hazards hazardous situation and hazardous events MACHINERY An assembly of linked parts or components at least one of which moves which have been combined to process treat move or package a material Also an assembly of such machines MACHINERY DIRECTIVE EU le
108. ositively driven contacts defines them as all or nothing relays with a combination of make contacts and break contacts where mechanical links ensure that if a Normally Open NO contact is closed then the Normally Closed NC contact cannot re close see Figure 5 3 If one of the NC contacts stays closed none of the NO contacts closes Many standard relays and all safety relays use this technology Under all operating and fault conditions a positively driven relay must have a contact gap of 0 5 mm for single break contacts and 2 x 0 3 mm for double break contacts the gap helps prevent arcing from the stationary contacts to the spanner 0 5 mm minimum lt NO NO single contact oo or Contact A 2 x 0 3 mm minimum Linked contacts Mechanical link double contact NC NC Contact B welded Positively guided contacts do not allow If contact B welded simultaneous closure of the NC and NO contacts then contact A stays open Fig 5 3 Positively guided relays 5 4 Anti tease features Clause 6 2 1 of EN 60947 5 which covers E Stops states that it shall not be possible for the emergency stop device to latch in without generating the emergency stop signal In case of failure the emergency stop device the generation of the emergency stop signal shall have priority over the latching means In addition clause 4 1 1 of EN 418 states that any action on the actuator which results in generatin
109. p light EN 1005 Human physical performance 3 parts Acoustics EN 2374X Acoustics Determination of sound power levels of noise sources EN 24871 Acoustics Noise labeling of machinery and equipment Electromagnetic Compatibility EN 5008 1 2 Electromagnetic compatibility Generic emission standard Part 2 Industrial environment EN 50082 2 Electromagnetic compatibility Generic immunity standard Part 2 Industrial environment Vibration EN 1031 Measurement of whole body vibration General requirements EN 1032 Testing of machinery in order to measure the whole body vibration emission value General requirements 105 Appendix B Electrical equipment of machines After completing a risk assessment covered in sections 3 8 3 12 of this book OEMs should fill out an Inquiry form for the electrical equipment of machines This is reproduced from the EN 60204 1 standard where it is designated as Annex B The form follows the standard and covers the sections which require special attentions The purpose of the form is to facilitate an agreement between the machine manufacturer and the control manufacturer The form is an excellent guide to cover all aspects of control product used on machinery and eliminate future disagreements Inquiry form for the electrical equipment of machines It is recommended that the following information be provided by the intended user of the equipment It
110. power supply For two or more disconnect interlocks may be required 5 3 2 Type of disconnecting device IEC 947 3 AC 23B or DC 23B Disconnector without fuses IEC 947 3 with interlock to the load switch Circuit breaker IEC 947 2 Plug and socket for 16 A or 3 kW max load for motors kW or HP rated 5 3 3 Disconnector marked with O and I External operating handle except power operated For an Emergency Stop the operator handle is red and the background yellow see 10 7 5 Means for locking in the OFF position disconnect all live conductors switch for motors kW or HP rated 204 1 Ref 5 3 4 Description of Standards Handle location between 0 6 and 1 9 m Applicable Applicable Approved 5 4 Prevention of unexpected start up disconnect Protection against electric shock 6 2 2 or 6 2 3 6 2 2 Protection by enclosures Top surfaces of enclosures are protected IP4X or IPXXD All live parts are protected to IP2X or IPXXB or Use of key or tool is necessary for access or Door mounted live parts protected to IP1X or IPXXA or
111. r components mean fewer fault combination permutations Dynamic techniques Relevant to equipment which must be complex to perform its primary task Particularly relevant to electronic technology Theoretical analysis and or testing 35 Category B No special measures for safety apply to parts complying with category B The parts when applied according to their specifications should be able to withstand the expected operating stresses e g load number of operating cycles the influence of material processed e g detergents in a washing machine and the relevant external influences e g vibration power disturbances Category 1 A well tried component for a safety related application is a component which has been 1 widely used in the past with successful results in similar applications or 2 made and verified using principles which demonstrate its suitability and reliability for safety related applications In some well tried components certain faults can be excluded because the fault rate is known to be very low Well tried safety principles are for example avoidance of certain faults e g avoidance of short circuit by separation reducing the probability of faults e g over dimensioning or underrating of components 36 orienting the mode of fault e g by ensuring an open circuit when it is vital to remove power in the event of fault detecting faults very
112. rea EEA The rules for the free movement of goods that apply to the EU also apply for the EEA Other countries such as Switzerland may adopt some or all of the directives in this case the same rules apply OEMs should check with the specific country for the applicable directives 21 So what directives should examine The directives are legal documents laws issued on the authority of the Council of the EU and adopted by the governments of all member countries They create a uniform level of requirements and regulations for all EEA members and supersede the previous national rules and standards which varied greatly The member states are obliged to transfer the directives into national law This facilitates the free movement of goods across international borders eliminating trade barriers The Machinery Directive official reference number 89 392 EEC with amendments is the most comprehensive directive for machinery using control products It states that all machinery marketed in the EU EEA must meet certain safety requirements These wide reaching requirements cover every aspect of the machine mechanical design electrical design controls safety and the potential for the machinery to create hazardous situations Note that while the directive discusses controls and safety components it does so in the context of designing a safe machine The Machinery Directive also identifies certain machines apparatus and applications
113. requirements will help machine designers select and or design safety related components Guide to the Categories for Safety Related Parts of Control Systems From EN 954 1 Category Basic Requirements Components able to withstand expected influences What is achieved Reliability for normal operation At most Reliability for normal operation Requirements of cat B together with Use of well tried e g tested or provable components and safety principles Enhanced reliability of the safety function from that of a normal device or system Elimination of fault possibilities i e high level of safety performance Requirements of cat B and the use of well tried safety principles together with A safety function check at machine start up and periodically if required Machine can only start when system is safe Machine can only start up when system is safe and faults will be detected by a frequent check i e high level of safety performance 34 Requirements of Cat B and the use of well tried safety principles together with A single fault will not cause a loss of safety function Detection of some single safety critical faults at the next demand on the safety function Safety critical faults can accumulate between demands on the safety function Non detected non safety critical faults can accumulate and cause loss of safety function Detection of ALL singl
114. risk category 4 No First why make a machine more complicated and expensive than necessary Second the ultimate objective is to offer a machine which functions reasonably safely Thus a well designed machine using highly reliable components and a well designed category 1 control system could perform better than and satisfy reasonable safety expectations as well as a machine with a category 4 control system Who can help me evaluate my machine Numerous companies and organizations provide this service Many of them originated in Europe Also some organizations specialize in a specific class of machinery Do need to hire a consultant The choice is yours If a manufacturing company feels it does not possess or cannot acquire the necessary expertise in house a consultant may prove valuable Can Rockwell Automation recommend a Notified Body Rockwell Automation does not endorse any particular Notified Body also the list of Notified Bodies changes frequently However searching the Internet is a good place to start The FEM brochure noted in section 3 2 of this book lists Notified Bodies and consultants also can provide recommendations 25 26 27 28 29 30 31 Can manufacturers do testing on site e g tests related to the Low Voltage and EMC Directives Yes However manufacturers may not possess the necessary test equipment In such a case they often turn to a third party or independent laboratory
115. rotective devices typically fuses or a circuit breaker to determine the coordination levels After a short circuit an interruption of service is unavoidable while the source of the failure is traced and cleared However the type of coordination will determine the length of the interruption see Figure 6 0 Type u Type 9 Type CPS e Trace and clear failure Xx after short circuit e Inspect starter e Exchange components e Break off welded contacts if any e Restart operation e Planned maintenance Fig 6 0 Short circuit coordination levels for motor starters After a short circuit with Type 1 coordination the starter components contactor overload motor protection circuit breaker may be defective and need replacing A restart is only possible after replacing starter components which could take some time if the components are not immediately available Type 2 coordination ensures that the starter components stay serviceable after a short circuit the contacts may weld slightly but they can be separated with a screwdriver No replacement parts are needed before restarting the machine Type CPS IEC 947 6 2 Control and Protective Switching devices CPS coordination devices ensure that the starter components stay serviceable after a short circuit that no replacement parts are needed before restarting the machine and that the starter will deliver additional operations at rated load without any inspection of compon
116. rt circuit current Availability of fuses 7 3 Overload protections of motors more than 0 5 kW where required Automatic restart shall be prevented 7 4 Abnormal temperature protection when required 7 5 Undervoltage protection when required 7 6 Overspeed protection when required 7 7 Earth fault protection when required 7 8 Phase sequence protection when required 7 9 Surge protection when required 8 2 2 Protective conductors cross section per IEC 364 5 54 or 7 4 3 1 7 of IEC 439 1 see Table 1 material copper 8 2 3 Continuity of the protective bonding All exposed conductive parts are connected to PE 8 2 4 In the PE circuit switching devices are not allowed Links in the PE circuit 8 2 5 Connection to PE is not required for conductive parts us Gg 204 1 Ref 8 2 5 Description of Standards Small sizes less than 50 x 50 mm Applicable Applicable Approved Can not be grasped Unlikely to contact live parts screws nameplates electromagnets etc 8 2 6 Interruption of protective circuit possible only after the live circuits have been interrupted reconnection is in reverse order plugs sockets 8 2 7 Protective conductor connecting points see 14 1 1 Identified by PE or 417 IEC 5019 or green and yellow
117. s 5 7 Control circuits and performance categories This section of chapter 5 reviews the category requirements then illustrates control circuits that can fulfill these requirements Please note that these examples are provided for educational purposes only and that control circuits using other designs may also fulfill performance requirements e State of the art components e Well tried components or principles e Check safety functions at suitable intervals e No loss of safety function through single fault e Detection of single faults or e No loss of safety functions through accumulation of faults Fig 5 5 Safety category requirements note the cumulative nature of the requirements 5 8 Category B and Category 1 Category B has no specific requirements beyond recommending the use of state of the art components Category 1 and all higher categories require the use of well tried components and principles It focuses on the prevention of faults through the use of well designed components Figure 5 6 shows the circuitry associated with a control relay The elements of the system include an E Stop an On Off pushbutton a control relay contactor a motor starter or other load and an overload relay Because the E Stop is relatively simple and tends to operate reliably the chance of failure leading to a dangerous condition is probably minimal assuming On Off pushbutton oe Fig 5 6 This control circuit c
118. s Machinery Directive and Annexes other directives Type A Standards EN 292 EN 1050 Type B1 Standards EN 954 EN 60204 Type B2 Standards Type C Standards Provide essential health amp safety requirements Are laws Applies to all machinery Broad safety principles for component safety and electrical equipment 27 Covers one safety aspect or safety related device Covers one type or class of machinery Standards are product product family specific Fig 3 4 Hierarchy of directives and standards CEN CENELEC divides the EN standards into three groups according to the subject s they cover and also makes them hierarchical in nature see Figure 3 4 To obtain CE marking manufacturers must determine which standards apply to their products then review and apply the appropriate ones Type A standards cover fundamental safety standards apply to all types of machinery and are essential reading The two most important Type A standards for manufacturers to review are EN 292 Safety of machinery discussed in section 3 1 and EN 1050 Safety of machinery Principles for risk assessment discussed in section 3 8 Type B standards are group standards and deal with only one safety aspect or one type of safety related device which can be used on a wide range of machinery see Appendix A of this book for a selected list of B standards The Type B standards fall into two classes B1 and B2 B1 s
119. s faced by the operator must be reduced to the minimum possible taking ergonomic principles into account e When designing and constructing machinery the manufacturer must take into account the constraints to which the operator is subject as a result of the necessary or foreseeable use of personal protection equipment such as footwear gloves etc f Machinery must be supplied with all the essential special equipment and accessories to enable it to be adjusted maintained and used without risk 1 1 3 Materials and products 1 1 4 Lighting 1 1 5 Design of machinery to facilitate its handling 1 2 Controls Reliability starting and stopping energy isolation control failures 1 2 1 Safety and reliability of control systems Control systems must be designed and constructed so that they are safe and reliable in a way that will prevent a dangerous situation arising Above all they must be designed and constructed in such a way that they can withstand the rigors of normal use and external factors errors in logic do not lead to dangerous situations 1 2 2 Control devices Control devices must be i clearly visible and identifiable and appropriately marked where necessary 130 positioned for safe operation without hesitation or loss of time and without ambiguity designed so that the movement of the control is consistent with its effect located outside the danger zones except for certain controls wher
120. s foreseen Guards or protection devices designed to protect exposed persons against the risks associated with moving parts contributing to the work such as cutting tools moving parts of presses cylinders parts in the process of being machined etc must be fixed guards wherever possible Otherwise use movable guards or protection devices such as sensing devices e g non material barriers sensor mats remote hold protection devices e g sensing device two hand controls or protection devices intended automatically to prevent all or part of the operator s body from encroaching on the danger zone 1 4 Required characteristics of guards and protective devices 1 4 1 General requirements 1 4 2 Special requirements for guards 1 4 2 1 Fixed guards 1 4 2 2 Movable guards 1 4 2 3 Adjustable guards restricting access 1 4 3 Special requirements for protection devices Protection devices must be designed and incorporated into the control system so that moving parts cannot start up while they are within the operator s reach the exposed person cannot reach moving parts once they have started up they can be adjusted only by means of an intentional action such as the use of a tool key etc the absence or failure of one of their components prevents starting or stops the moving parts 1 5 Protection against other hazards 1 5 1 Electricity supply 1 5 2 Static electricity 1 5 3 Energy supply ot
121. s of power devices like contactors circuit breakers or switches as well as the contacts of relays and sensors have to work reliably at these signal levels The same contacts must perform reliably at conventional loads with high AC 15 ratings Devices using cross stamped and H bridges see photo on next page perform excellently under these conditions and improve reliability and safety control circuits Cross stamped left and H bridge contacts Multiple fault detection The EU standards suggest incorporating different types of safety functions to avoid hazards As an example a high end motor protection device offers a number of functions to avoid hazards at an early stage Besides overload and short circuit protection motor protection relays offer stalling protection and underload protection Stalling protection prevents mechanical parts from breaking by very quickly switching off the motor when it senses excessive torque i e it could avert the breaking of mechanical parts that if they broke might endanger persons nearby Underload protection responds to situations where the failure of mechanical transmission elements or part breakage e g a drill bit chain pulley etc could lead to dangerous situations Motor protection Motor starters motor protection are available with short circuit coordination levels of Type 1 Type 2 and CPS The contactor and overload relay are tested with appropriate short circuit p
122. safeguards to provide the risk reduction Those parts of the control system which contribute as an integral part of the design measures and or in the control of the safeguards shall be considered safety related parts Step 3 Specify safety requirements for the safety related parts of the control system Specify the safety functions to be provided in the control system Appendix E provides a list of typical safety functions which can be provided by the safety related parts of a control system The list also references the relevant parts of standards Specify how the safety functions will be realized and select the category ies for each part and combinations of parts within the safety related parts of the control system Step 4 Design Design the safety related parts of the control system according to the specification developed in step 3 and to the general strategy for design List the design features included which provide the design rationale for the category ies used Verify the design at each stage to ensure that the safety related parts fulfill the requirements from the previous state in the context of the specified safety function s and category ies Step 5 Validation Validate the achieved safety functions and category ies against the specifications in step 3 Re design as necessary When programmable electronics are used in the design of safety related parts of the control systems other detailed procedures are
123. stem with one point directly earthed with a protective conductor PE connected directly to that point TT System with one point directly earthed but the protective conductor PE not connected to that earth point of the system IT System that is not directly earthed Is the electrical equipment to be connected to a neutral N supply conductor 5 1 YES NO Does the user or the supplier provide the overcurrent protection of the supply conductors 7 2 2 Type and rating of overcurrent protective devices Supply disconnecting device Is the disconnection of the neutral N conductor required YES NO Is a link for the neutral N permissible YES NO 17 Type of disconnecting device to be provided 18 Limit of power up to which three phase AC motors may be started directly across the incoming supply lines kW 19 May the number of motor overload detection devices be reduced 7 3 YES NO 20 Where the machine is equipped with local lighting highest permissible voltage V if lighting circuit voltage is not obtained directly from the power supply state preferred voltage V Other Considerations 21 Functional identification 17 3 22 Inscriptions special markings 23 Mark of certification YES NO If YES which one On Electrical Equipment In which language 24 Technical documentation 18 1 On what media In which language 25 Size location and purpose of ducts open cable trays or cable supports to be provi
124. t external influences 12 2 1 Accessibility and maintenance located between 0 4 and 2 0 m above service floor level plugs not interchangeable test points marked 121 E 204 1 Ref 12 2 2 Description of Standards Physical separation and grouping Applicable Applicable Approved Non electrical devices are not permitted in the electrical enclosure terminals grouped power circuits associated control circuits other control circuits external sources etc 12 2 3 Heating effects each components remain within permitted temperature limit 12 3 Degrees of protection P22 minimum 12 4 1 Enclosures doors and openings Captive door fasteners Windows polycarbonate 3 mm Doors 0 9 m wide max 12 4 2 Access to control gear per 2 4 of IEC 364 4 481 13 Conductors and cables 13 1 Voltage current temperature 13 2 Conductors copper temperature per Table 4 for frequent movement flexible Class 5 or 6 Table C 4 13 3 Insulation approved 13 4 Current carrying capacity in normal service Temperature in Table 4 is not exceeded Current ratin
125. tals with manual loading 143 and or unloading whose movable working parts may have a travel exceeding 6 mm and a speed exceeding 30 mm s 144 10 11 12 13 14 15 16 17 Injection or compression plastics moulding machines with manual loading or unloading Injection or compression rubber moulding machines with manual loading or unloading Machinery for underground working of the following types machinery on rails locomotives and brake vans hydraulic powered roof supports internal combustion engines to be fitted to machinery for underground working Manually loaded trucks for the collection of household refuse incorporating a compression mechanism Guards and detachable transmission shafts with universal joints Vehicles servicing lifts Devices for the lifting of persons involving a risk of falling from a vertical height of more than 3 meters Machines for the manufacture of pyrotechnics Safety components l a A W N Electrosensitive devices designed specifically to detect persons in order to ensure their safety non material barriers sensor mats electromagnetic detectors etc Logic units which ensure the safety functions of bi manual controls Automatic movable screens to protect the presses referred to in 9 10 and 11 Roll over protective structures Falling object protective structures Appendix H IEC Style Diagrams from Chapter 5 Overload On Off
126. tandards deal with one particular safety aspect such as the effectiveness of safety functions safety distances hand arm speed noise etc The two most encompassing Type B1 standards are EN 60204 1 Safety of machinery Electrical equipment of machines and EN 954 1 Safety of machinery Safety related parts of control systems Part 1 General principles for design Appendix B of this book provides an electrical equipment checklist based on EN 60204 1 that will help designers conform with the standard B2 standards deal with safety related devices e g interlocks emergency stops various safety switches two hand controls proximity devices again see Appendix A If manufacturers use one of these safety devices on a machine then the device must be designed and applied according to the relevant standard EN 60204 electrical checklist EN 60204 1 which is comparable to IEC 204 provides a very comprehensive list of electrical equipment design aspects to which manufacturers should adhere Appendix 2 of this book provides a checklist for designers based on this standard as well as an inquiry form that OEMs should give to end users of electrical equipment While Type A and B standards cover most types of machines and relevant safety standards Type C standards give detailed safety requirements for specific types of machines Type C standards are based on applicable sections of relevant Type A and Type B sta
127. tching off o 10 8 1 Location as necessary 10 8 2 Types push button pull cord positive direct operation per IEC 947 5 1 and self latching Glass enclosure allowed 204 1 Ref Description of Standards Applicable Applicable Approved 10 8 3 Restoration of normal function after emergency switching off only after manual reset 10 8 4 Actuators red background yellow push button mushroom type 10 9 Visual displays visible from the position of the operator 11 Electronic equipment 11 2 1 The status of the digital inputs and outputs should be indicated 11 2 2 Equipotential bonding All input output processor power supply racks shall be bonded and earthed see 8 2 3 and exclusions 11 3 Programmable equipment 11 3 1 Programmable controllers per IEC 1131 1 and 2 11 3 2 Memory retention and protection per 9 4 3 2 11 3 3 Software verification required for reprogrammable logic 11 3 4 Use in safety related functions shall not be used for Category 0 emergency stop function 12 Control gear location mounting and enclosures 12 1 Accessible for use Accessible for maintenance Protected agains
128. te that by its design and construction the product is capable of being installed put into service and operated safely Determination of the foreseeable lifetime of the product A copy of the instructions for the product Instruction Manuals Instruction Books For serial manufacturing the internal measures that will be implemented to ensure that the equipment will continue to be manufactured in conformity with the provisions of the Machinery Directive and other applicable directives K Engineering Reports L Laboratory Reports Testing components M Bills of Material Machine manufacturers must N Wiring Diagrams evaluate the applicability of components and fittings on the O Sales Order Engineering Files completed machine to determine if P Hazard Evaluation Committee the machine can be put into service safely This helps to ensure that Reports if executed machine manufacturers cannot pass on safety responsibilities to their O Change Records vendors For companies that R Customer Specifications manufacture a series of machines the company must show the measures S Any Notified Body Technical ee it plans to use to ensure that the Reports and Certification Tests 4 machinery remains in conformity if applicable T Copy of the Declaration of Conformity Important items to note about the TF e The documentation noted above need not permanently exist in the TE 50 However the man
129. that do not fall within its scope For this equipment other directives may apply such as the Electromagnetic Compatibility EMC Directive 89 336 EEC and the Low Voltage Directive 73 23 EEC as well as directives for batteries explosive atmospheres simple pressure vessels personal protection equipment and dangerous substances Manufacturers must take care to learn about all directives which apply to their product Machinery builders must thoroughly familiarize themselves with the Machinery Directive and associated standards 2 2 Standards to clarify directives To help clarify and expand on the essential requirements set forth by the directives and to provide a means of testing verifying that machinery meets directive requirements OEMs can refer to a set of harmonized European standards European Norms or ENs Developed by the European Committee for Standardization CEN and the European Committee for Electrotechnical Standardization CENELEC the standards are voluntary not law However standards are the most expedient means to show compliance with the Machinery Directive When OEMs design machinery according to EN standards conformity is presumed Two fundamental safety standards apply to all electrical controlled machinery e EN 292 1 2 Safety of machinery Basic concepts general principles for design Part 1 Basic terminology and methodology Part 2 Technical principles and specifications EN 1050 Saf
130. to a protective earth grounding is required Another choice for preventing hazardous touch voltage require Class H equipment double or reinforced insulation per IEC standard 536 If one insulating system fails the other insulating system provides full protection against electrical shock Alternately preventing hazardous touch requires using assemblies having total insulation per IEC standard 439 1 or using supplementary or reinforced insulation per 413 2 of IEC standard 364 4 41 Control and load switch which could be applied IEC Contactor with IP as a hand operated disconnect or as an Emergency 2LX finger protection Stop when using the red actuator as shown against accidental contact with live components 20 Tso F Manual motor starter with magnetic trip and bi metallic overload protection When properly applied with the contactor shown on the left it provides Type 2 coordination The hazardous touch voltage can be avoided by electrical separation per 413 5 of IEC standard 364 4 41 too Further it can be avoided with a construction where in case a live part comes in contact with an exposed conductive part the contact will not create hazard An isolating source like an insulating transformer which is not grounded or other measures stated in the standard provides this type of protection The voltage is limited to 500V in these circuits Electronic motor manager an electronic overload protection relay w
131. to perform the test Are the EU directives spreading to other countries i e Australia No The directives are laws specific to the EU The European Norms most of which are based on JEC standards naturally resemble standards used by many countries What standards address which products Do the standards vary by location The list of standards is exhaustive Appendix B of this handbook provides a short partial list of those most likely to relate to machine builders Section 2 3 of this handbook notes sources that can provide you with the complete standards list For any country requiring CE marking use the European Norms IEC or ISO standards may also be acceptable What is the penalty for not having CE marking on my machine EU customs officials will not allow the machine to enter the market nor will they permit such a product to be placed into service in the EU What is the penalty for failing to comply with the Machinery Directive but placing CE marking on the machine Article 7 3 of the Machinery Directive a law states that where machinery which does not comply bears CE marking the Member State shall take appropriate action against whomsoever has affixed the marking and shall so inform the Commission of the EU and the other Member States How do minimize my legal exposure Meet the requirements stated in the directives How are the standards being enforced The EU does not enforce standards they enforce dire
132. ufacturer must be able to assemble the documentation or specific portions of it and make it available within a period of time commensurate with its importance one week is considered a reasonable time As a minimum each machinery TF must physically contain an index of the applicable documents or material listed above e The TF may be in hard copy or software form provided that the software form can be easily reproduced in hard copy e Only the National Authorities duly authorized agents of member states have the right to see the contents of the TF The National Authority must specify what portion of the TF is required and a suitable reason for the request The Directive does not give the client user or others the right to see the file e The Technical File must be maintained at the location of the product machinery design e The TF including all documentation must be retained and kept available for 10 years following the date of placing the product in the EU or from the last unit produced in the case of series manufacture e The TF must be drawn up in one of the official languages of the EU English French or German e The EU is currently considering a proposal whereby EU inspection authorities should accept subdivision of the TF into two parts The first part A would consist of a summary of the essential technical data relevant to the conformity assessment procedures in particular a product description the
133. used for fault detection a Automatic fault detection as far as it is appropriate b Manual fault detection e g by periodic inspection c By more than one method 9 Has the risk reduction been achieved a Can the risk reduction be achieved more easily with a different combination of risk reduction measures b Check that the measures taken do not reduce the ability of the machine to perform its function do not generate new unexpected hazards or problems c Are the solutions valid for all operating conditions and for all procedures d Are these solutions compatible with each other e Is the safety specification correct 10 Have ergonomic principles been considered 11 a Are the safety related parts of the control system including the protective devices easy to use b Is there safe and easy access to the control systems c Are warning signals given priority e g highlighted Have the relationships between safety reliability availability and ergonomics been optimized in such a way that the safety measures will be maintained during the lifetime of the system and does not tempt personnel to defeat the safety functions CE conformity is your passport to the European market but you still must create a Technical File produce and sign a Declaration of Conformity and adhere to other EU rules Post Design and Construction Requirements So you ve complied with requirements

SHB-900 - Rockwell Automation

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